New debugger functionality based on CDT GDB support

Here it is, as new debugger functionality based on CDT, as described here:
https://groups.google.com/forum/#!topic/goclipse/K90ar6u6VPk
A few notes:
The src-lang/ code may look a bit strange, but it is just a way to make it easy to share language indepedent code between IDEs. This is described in more detail in: https://github.com/bruno-medeiros/DDT/#about-src-lang-and-melnormelang-code if you wanna understand better how its done.

I'm looking to do some further improvements on debug/launch functionality, namely:
*add a debug hover in the Go editor (display value/toString of local variables, similar to a detail Variables view)
*refactor and fix some issues around the launch tabs. There's a few bugs I found (that existed before this branch), like an NPE on new launches, and the tab asking the configuration to be saved even though no changes ocurred.

But this pull request stands on its own, and fixes the debug issues mentioned in the GoogleGroups thread.