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
[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)"
[GEOS-5159] changes from GEOS-4100 breaks LegendDecoration with custom DPI
[GEOS-5197] Use the layer abstract as the GeoRSS channel description
Fixed a few typos in the developer/policies directory
Added support for LayerGroup to the WMS GetLegendGraphic action
Adding examples for WFS 2.0 operations
Fixing typo in WFS reference
User Guide - added Filter Encoding reference section
import geoscript's geometry class
GEOS-5533: fixed critical bug in FreemarkerTemplateResource