This aims to prevent extending UserDefinedFunction for UDFs whose translation
is very simple (e.g. different name in SQL, different argument order, etc).

Fixes #115

This commit reverts commit 89418d13.

The reverted commit will be applied in another branch (probably 'adql-2.1') as
it is part of the next release of ADQL-Lib.

- Now, `ADQLParserFactory.createParser(...)` should be used to create a parser
- Only the new function `LOWER` is supported for the moment
- Not yet possible to manage the optional features _(next dev to come)_
=> 1st step for ADQL-Lib v2.0

- TAP adapted so that using the last stable version of the ADQL language
  (i.e. 2.0 for the moment)
  - but not yet possible to set the ADQL version to use in the configuration
    file

`fix_on_fail` in the configuration file. By default, this feature is disabled.

_With 15cd5944, this commit finishes the resolution of the GitHub issue #104 ._

The property `upload_default_db_limit` has been deprecated. Indeed, in the
current state of the TAP protocol, this makes no sense: the user can not change
the limit size (in bytes or rows) for uploaded tables.

The property `upload_max_file_size` has been deprecated. It is actually
duplicated: `upload_max_db_limit`, if expressed in bytes already lets put a
limit on the maximum size of an uploaded table/file.

The property `upload_max_request_size` has been added. It lets set a maximum
size for a whole HTTP Multipart Request. By default it is set to 250MB.

The default value of `upload_max_db_size` is now 1 million rows.

The UPLOAD feature is still disabled by default (i.e. `upload_enabled=false`).

The end of the description of a UDF was not detected when this UDF was followed
by another UDF definition. This was due to an incorrect double quote escape in
the regular expression of a UDF's definition.

Although the Java code allowed the specification of a description of a User
Defined Function, it was not possible to set one in the UDFs listed in the
configuration file.

This commit resolves partially the issue #28

Ideally, there should be an implementation of UWSLog and TAPLog working with
Log4j and another for SLF4J (and eventually for other logging mechanism).
Additionally, an implementation storing log messages in database would be
interesting. All these ideas may be implemented in UWSLib and TAPLib in a
future version.

The JUnit test should have been updated as well.

TAP capabilities resource content.

TAP capabilities resource content.

- empty file
- not a valid VOTable document

In such cases, the following error message is returned:
  "The input file is not a valid VOTable document!"
A cause with more detais (especially the line and column numbers)
may be appended.

Cases handled with no error:

  - If the VOTable document has no rows, an empty table
    is uploaded. No error has to be returned.

  - If a row has a different number of columns than the number
    of declared FIELDs, additional values are ignored and missing
    values are replaced by NULL. This is actually nicely handled by
    STIL.

apply a quick space replacement (by %20) for few URIs of the configuration file
and remove duplicated entry (encoding) from the Gradle build script.

A special test has also been added in getFile(...) in order to deliver
a clear error message for users using a former version with URIs in their
configuration file (only for file_root_path and metadata_file).

Two embedded DBMS are used: H2 and a little SQLite. JDBC drivers are provided
in the `lib` directory. The databases are created and deleted automatically
by the JUnit tests (see `test/tap/db_testtools/DBTools for more details`).

The ANT and Gradle build scripts have been updated to reflect all these test
modifications.

ResultSetTableIterator (i.e. functions returning unknown numeric values
were not set with the right datatype but char* instead).

Date and Time are converted into a string with the following resp.
formats: 'yyyy-MM-dd' and 'HH:mm:ss'.

2463d5fe

column in TAP_SCHEMA. Such names are normalized (without any prefix and without
double quotes) when getADQLName() is called, but are returned just trimmed
by getRawName(). This latter is just used by TAPMetadata when writing the XML
description of all TAP tables.

in DBType.DBDatatype (for UNKNOWN and UNKNOWN_NUMERIC). This reset is performed
after each JUnit setting a special custom value (otherwise it prevents other
JUnit to run correctly)

with a constructor (ServiceConnection, Properties)).

by the TAP configuration file in order to add/remove/change some metadata or
to change the output of the TAP resource '/tables'.

time shifts (summer/winter time) when any.

[TAP] Add Javadoc for all TAP configuration file related classes + Improve the function ConfigurableServiceConnection.getFile(...) + Set the default value of limits/durations/periods to the maximum value if the new maximum value is less than the current default value.

[TAP] Incorrect setting of the backup frequency. The documentation was also incomplete about this property, but also wrong concerning the property backup_mode which is actually backup_by_user.

[TAP] Add the possibility to set the FetchSize on a DB Statement for the execution of ADQL queries. It is also possible to set a fetchSize different for synchronous and asynchronous queries.

[TAP] Add a configuration file property: 'coordinate_systems'. It lets list all allowed coordinate systems. By default, the list is empty, meaning that any is allowed.

[TAP] Change the default value for output and upload limits ; only negative value must mean 'no restriction' ; 0 must be a normal allowed value.

[TAP] Allow the TAP configuration file properties 'file_root_path' and 'metadata_file' be file pathes relative to WebContent.

[ALL] Update ANT build scripts to test all existings JUnit tests before compiling. In case of error, the compilation does not complete.

[TAP] Add a property in the configuration file to set a custom TAPFactory (in replacement of ConfigurableTAPFactory.

[TAP] Add a 3rd possibility to set metadata in the TAP configuration file: give an extension of TAPMetadata having either an empty constructor or a constructor with a UWSFileManager, a TAPFactory and a TAPLog. & Rename function TAPConfiguration.isClassPath(String) into TAPConfiguration.isClassName(String).

[TAP] Add property to add/replace TAP resources & Add the tool function TAPConfiguration.newInstance(...).

[TAP] Add log management in the TAP configuration file. 2 additional properties have been added: min_log_level and log_rotation.