Merge pull request #29 from agueganno/projection-management-improvement

Namespace displaying seems to appear randomly...
Adds some keys in the configuration file.
I retrieve them when launching the app in order to instanciate cleanly
the WMS Context.
Use the configuration variables currently defined.
The getCapabilities response is built using them.
Fix a call in Global.scala too.
Adds EX_GeogarphicboundingBox where it is needed.
I think that our getCapabilities document is now valid against the norm.
Improve namespace bindings
That's not the cleanest work of my life... but changing namespace
definition in JAXB is not that simple. It is working. It is expected to
be done that way, according to java.net. It may break someday, but
currently it's operational and we need it if we want QGIS to be able to
connect to our server, as there is a bug in its WMS client.