Remove SWT dependency from muggl-common project

[vvhof]

From the description, I'd deduct that the specific code could be adapted to employ a different library for the purpose of RGB color representation, so that this specific dependency may be omited.

[Dagefoerde]

For the solvers project this is now done.
For the common project this is still an open issue. I would recomment using java.awt.Color instead, since they manage RGB similarly (but not identically).

This is now pending @anfuchs' changes to the ConfigReader, as I do not want to mess up working code while he is switching to an XML parser.