Fix GRAILS-10763 problem with comments inside UrlMappings configuration.

This patch fixes the issues with the comments inside the UrlMappings and the problems with the regular expressions of my first patch.

On the last test in "UrlMappingsGrailsPluginTests.groovy" reproduced the issue with the stackoverflow problem with the regexp. I've left the test in order to be more strict (doing a broken test and then solving the problem).

The final solution compiles de different files *UrlMappings.groovy and creates their AST. Then a visitor find the "response codes" and uses them inside the plugin to create the final web.xml

http://jira.grails.org/browse/GRAILS-10763