[API,FEATURE] added new function 'updateProteinGroups'
[FIX-#748] update (indistinguishable) protein groups after filtering protein hits
[INTERNAL,DOC] removed warning message about invalidating protein groups in 'ProteinIdentification::setHits', added a note to the documentation instead
Merge branch 'develop' of https://github.com/OpenMS/OpenMS into fix-idfilter-groups

Conflicts:
	src/openms/source/FILTERING/ID/IDFilter.cpp
[FORMAT,TEST] set scores of indistinguishable proteins to score of the leader when reading protXML
[FIX] adjusted warning message: protein grouping isn't invalidated by removing whole groups
[TEST] added test case for updating protein groups in IDFilter
[TEST] added test for 'updateProteinGroups' function
[TEST,NOP] coding style (whitespace fixes)
[API] made all methods of class 'IDFilter' static
Merge pull request #1086 from hendrikweisser/fix-idfilter-groups

Update (indistinguishable) protein groups when filtering protein identifications (fixes #748)