[GEOS-5993] Missing ElectronicMailAddress in WFS capabilities

In the WFS capabilities there were missing two important fields that are
present in the XSD. Those fields are ElectronicMailAddress and
DeliveryPoint.

This commit adds those two fields, but disregards the fact that there
can be more than one of both fields. However this patch could be adapted
to create a List or Array of both, so they are more faithful to the XSD.
[GEOS-5993] Added a test in the WFS Capabilities Transformer test for Contact information added to WFS.
[GEOS-5993] Added GUI support for DeliveryPoint and ElectronicMailAddress.
Implemented hashCode and equals methods.
Updated SLD cookbook 3-color gradient to match current behavior
[GEOS-6776]: Restoring grib community module in the release, previously removed due to issues with the opengeo to boundless switch
[GEOS-6779]: Fixing NetCDF WCS request after fix made with GEOS-6757
Fixing community processes using the old storage cleaner hack to save raw outputs
Merge pull request #824 from dromagnoli/GEOS-6776

[GEOS-6776]: Restoring grib community module in the release, previously ...
[GEOS-6781] WPS does not report progress of chained processes
GEOS-6775: removed wrong content-length header from gzipped content
Merge pull request #827 from mbarto/geos6775

GEOS-6775: removed wrong content-length header from gzipped content
Update grib.rst
Merge pull request #829 from bradh/patch-3

Update grib.rst
Merge pull request #825 from dromagnoli/GEOS-6779

[GEOS-6779]: Fixing NetCDF WCS request after fix made with GEOS-6757
[GEOS-6783]: Fixing imageLayout on coverageViewReader
Fix data directory path example for Linux

See http://docs.geoserver.org/latest/en/user/datadirectory/data-dir-creating.html for how this gets rendered.
Merge pull request #830 from dromagnoli/GEOS-6783

[GEOS-6783]: Fixing imageLayout on coverageViewReader
Update Page Header for 2.7
Merge pull request #820 from smithkm/master

Update Page Header to reflect version