Don't apply scalefactor on legend keyimage (#4885)
Fix failed assertion with non-existant svg symbols (#4899)
Implement WCS20 Extensions (#4898)

- Add parsing capabilities for WCS RangeSubset extension.
- Implement WCS geotiff extension.
- Properly implement CRS extension.
- Fix Profile URIs for WCS 2.0
- Fix subsettingcrs KVP parameter name.
- Proper implementation of scale extension.
- Fix index for rangesubset intervals. Also allowing integers as band identifiers.
- Fix geotiff:predictor parameter. Should now be one of 'None', 'Horizontal' or 'FloatingPoint' as required in the spec.
add scripts to provision a mapserver vagrant instance
Merge branch 'branch-6-4'

Conflicts:
	maplegend.c
master specific vagrant changes
vagrant: use an automatic mirror for downloading debs
Merge branch 'branch-6-4'
Fix segfault when setting a utfitem not present (#4904)