Fixing bugs in referenceable dataset renderers.
Merge branch 'master' of git+ssh://github.com/EOxServer/eoxserver
Removing debug prints.
Fixing HTTP return code for NoSuchCoverageOrDatasetSeries exceptions.
Fixing WCS for ref coverages.
Fixing various WCS rendering issues and errors. Cleanup.
More strict checking of subset X/Y CRS.
Adding functions to determine whether or not a CRS is a imageCRS. Fixed missing import.
Fixing implementation for referenceable datasets.
Fixing typo.
Adding render options model. Using render options in various WMS layer setups. Fixing exceptions.
Adding exception classes for invalid formats/CRSs
small beautifications.