Allow StyleGenerator to create style inside of a workspace.
Merge pull request #776 from jdeolive/style-gen-workspace

Allow StyleGenerator to create style inside of a workspace.
Added DataStoreFactoryInitializer for GeoPkg. Fixes GEOS-6708.
 - improved importer and test-cases
Merge branch 'master' of https://github.com/geoserver/geoserver into wps-resource