[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.
Merge pull request #762 from Geodan/GEOS-5993

[GEOS-5993] Missing ElectronicMailAddress in WFS capabilities
Merge branch 'master' of git://github.com/geoserver/geoserver