Fix wms driver

In fact, I've done a bit more than just fixing it. First, I've removed our dependency to an old library that came from gvSIG. We've got some problems with it, and it was not the most efficient client...
We decided to switch to the openJUMP client. Here again I've been forced to take the code from the original software as it was not packaged in a dedicated library. I've cleaned it, integrated it in our WMS driver and added WMS 1.3.0 support in it. It seems to be working but it definitely needs to be tested. There are not any unit tests nor here neither in openJUMP testing this codes.

Note that you'll be facing problem I won't be able to solve. Most of them will be linked to projections (and to geotools, consequently). Some of them are linked to the servers themselves. I've found a MapServer instance that replies with an exception when requesting a map with a BBOX that is not exactly the bounding box of the asked layer. This server identifies itself as a 1.3.0 server sometimes and as a 1.1.1 server the rest of the time. Another server I've tested gives some empty SRS tags. Don't know how it's possible...