Automatically discover *taglib.xml in META-INF

The JSF 2.0 spec unthinkingly copies the original facelets behavior for
discovering *taglib.xml files: either as listed in web.xml or in META-INF
directories of JAR files. For custom component tutorials, it would be desirable
to also allow *taglib.xml files inside the META-INF directory of the web
application itself. It's a trivial enhancement that makes it just a bit easier
for people to learn about custom component development.
#### Environment
Operating System: All
Platform: All
#### Affected Versions
[2.0]

Review the JSF 2.0 taglib discovery rules described here, including web.xml entries and META-INF directories in JAR files. Then locate the existing discovery entry point and tests, and verify that a *taglib.xml file in the web application's own META-INF directory is discovered without a web.xml entry.

Written by the indexing model from the issue text.