plug in the url manglers with gwc's hook

GWC now has a hook for altering the urls that it generates. This plugs
into that hook, and delegates to the geoserver response utils chain,
which calls all the geoserver pluggable extensions.
added WMS and WMTS support for URL mangling
Fix for URL mangling base paths, and adding WMS and WMTS mangling
Add GeoScript to the Groovy Script module
Merge branch 'master' of git://github.com/geoserver/geoserver into script_groovy
Add license headers
Fix failing test
Merge branch 'master' into gwc-url-mangling-master
replaced hardcoded geoserver version number.
GEOT-4358: added style test for isCoverage filter function
Switching gif files to png since pdf2latex cannot handle gif files
Fixing schema location in DescribeCoverage output
Follow up to GEOS-5346, WCS 1.1 resolution estimation broken on reprojection, to handle rotated coverages as well
Fixing one of the WFS 1.0 failures, inability to deal with repeated request=DescribeFeatureType in the request
Make DDS compile again
Improving error message for accepts versions not found
Added WFS 2.0.0 reference
Resolving Sphinx errors
Aligning fixed references between branches
[GEOS-5371] Reloading config break status config page (porting test over, trunk was not breaking but we want to make sure we don't have regressions on this error)"