Fix Memory leak in UVRaster layers (#4706)
Fixing interpretation of return value for `msWCSParseRequest20`. `MS_DONE` now means that the exception has already been written to the IO buffer.
Directly rendering exception messages during parsing. Wrong 'mediatype' values now produce exceptions. Fixing HTML status codes for various exception types.
Fixing typo.
Updating msautotest submodule.
Fix some warnings
Adjusting exceptionCode in WCS 2.0.
Merge pull request #4719 from EOX-A/branch-6-2-error-handling

Adjust error handling in WCS 2.0