Develop the wcsproc extension

[Jinsongdi Yu]

The post requet as below should be supported:
<proc:ProcessCoverages

xmlns:wcs="http://www.opengis.net/wcs/2.0"
xmlns:gml="http://www.opengis.net/gml/3.2"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:proc="http://www.opengis.net/wcs_service-extension_processing/2.0"

service="WCS" version="2.0.1">

<proc:query>

for c in (mean_summer_airtemp )
return encode (c, "png")

</proc:query>

</proc:ProcessCoverages>

[Peter Baumann]

This is dependent on ongoing work in OGC standardization: the WCS request type is defined in the WCS Processing Extension which has been brought up to speed with WCS 2 (WCPS had been established 2 years before that). This extension is currently under public Request for Comment (RFC). Once done, we will collect any eventual change requests, incorporate, and go to voting. Once we have a reasonbly stable basis (possibly even before voting, but after RFC) we can start implementation.

[Piero Campalani]

Closing this as superseded by #614.