More eclipse setup code

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A few notes:
* Calling cleanEclipse does not delete the previously copied Terasology.launch file. Docs say it must be defined as output.

* Ignored warnings for project "engine" only. It would be better to apply this to all eclipse subprojects. It seems as if this was not trivial to accomplish.

* Quite a few of the suppressed warnings appear to be important (potential heap pollution, stream not closed, etc). However, it's difficult to verify that fixing dozends or hundreds of warnings that are scattered all over the place doesn't break anything.