fix segfaults in XTandemXMLFile and IsobaricChannelExtractor
Merge pull request #1116 from cbielow/fix-WindowsCompile

fix segfaults in XTandemXMLFile and IsobaricChannelExtractor
Merge branch 'develop' into fix/compile_warnings

Conflicts:
	src/openms/source/FORMAT/XTandemXMLFile.cpp