[GEOS-6341] Associate css style as default for a layer from the css demo page
[GEOS-6330]: REST HTML interface links to coverages contain coveragestores against instead of coverages
Merge pull request #478 from aaime/css_associate

[GEOS-6341] Associate css style as default for a layer from the css demo...
Merge pull request #479 from dromagnoli/GEOS-6330

[GEOS-6330]: REST HTML interface links to coverages contain coveragestor...
[GEOS-6344] PNGJWriter logs exceptions at warning level even if the client closed the connection
Removing warnings about missing formats in GeoServer preview page
consolidate error handling and some cleanup

- put uncaught exception handling into BaseResource and ensure
  uncaught exceptions are logged during testing
- remove redundant finders from spring and routing config
- remove instance state from ImportResource + minor refactor to
  accomodate
- push logger up to BaseResource
- imports cleanup