[TAP] New feature: Examples endpoint.

Can be enabled just by providing a file URI in the TAP configuration file using
the property "examples". It is also possible to add manually a TAP resource
whose the returned name must be "examples" like the new TAP resource is doing:
tap.resource.Examples. This latter take a file URI as the TAP configuration
file does. The referenced file must respect the DALI 1.0 or TAP Notes 1.0
syntax. No check of the file is performed by the library ; it is up to the
author of the referenced file (a XHTML/RDFa file) to write a correct "examples"
endpoint content. Check out the examples provided on the GitHub repository in
the directory examples/tap/examples_endpoint.