[NOP] code formatting
[FEATURE,TEST] refactored AASequence creation from string, increased robustness of parsing (fixed #818), updated tests
Merge branch 'develop' of https://github.com/OpenMS/OpenMS into AASeq-robustness
Merge branch 'develop' of https://github.com/OpenMS/OpenMS into AASeq-robustness
[DOC] updated AASequence documentation
[TEST] removed tests of 'AASequence::fromUnmodifiedString'

'fromUnmodifiedString' was not needed after rewrite of 'fromString' and was not merged in
[INTERNAL] removed 'AASequence::parseUnmodifiedString_' (no longer needed)
Merge branch 'develop' of https://github.com/OpenMS/OpenMS into AASeq-robustness
Merge pull request #875 from hendrikweisser/AASeq-robustness

Rewrite of 'AASequence::parseString_', increasing robustness of parsing (fixes #818)