Adding HTTP DELETE support to ProxyServlet.
Adding HTTP PUT support to ProxyServlet.
[FABRIC-1052] Clean all resources which were locked during Fabric recreation
Adding support for HTTP OPTIONS method.

Motivation:
The proxy should be able to proxy OPTIONS request especially as this
might otherwise stop target services that use Cross Origin Resource
Sharing (CORS) from working.
To enable CORS we also had to remove the filtering of the 'ORIGIN'
request header and allow it to added to the proxied request.
#1102: Fixed container login on git http server, so it also works when starting fabric with bin/fabric8 that may cause JAAS to be not initialized asap, which would cause git http server to fail authentication and git sync not to work. Thanks to Ioannis good idea how to get this fixed.
Process test API now uses FabricConstants.
Initialized test ProcessManagerService.
AbstractProcessTest doesn't have to catch IllegalThreadStateException anymore!
Fixed Javadoc.
Improved jvm.config generation.
Refactoring.
[FABRIC-1051] invoke Git-GC after every 40th commit