msProjectionObj2OGCWKT_ImportFromEPSG

This changes msProjectionObj2OGCWKT() to use OSRImportFromEPSG() when possible (i.e. when the projection is defined as +init=EPSG:XXXX).

This helps when using OGR OUTPUTFORMAT with some formats that need an EPSG code to be explicitely set in the OGRSpatialReference object.

The updated tests are there : https://github.com/mapserver/msautotest/commit/303ae5e8b04ee51c19a98625546e3a8ddc26bc03

One can notice a few changes in some WFS OGR output that show the benefit of having the EPSG code set.

This also causes a number of updates in the WCS test-suite : they are due to the citation part of the SRS encoded in GeoTIFF being drawn now from the EPSG database instead of the name that PROJ.4 tried to build (and that is often inferior).