[FEATURE] new option (intensity weighted mean) added
[INTERNAL] intensity weighted mean calculated
[INTERNAL] parameter renamed
[INTERNAL] coding style changes
[DOC] minor doc change
[TEST] test for weighted_mean added
[TEST] test data changed
[TEST] test corrected
[TEST] test corrected
Merge pull request #1074 from lars20070/feature/ProteinQuantifier_IntensityWeightedMean

'intensity weighted mean' averaging added to ProteinQuantifier, solves #830