[FEATURE] add chaining consumer

- allows to chain multiple consumers
[DOC] add documentation for chaining
[TEST] add test for MSDataChainingConsumer
[INTERNAL] move code to cpp file
[DOC] better error handling in TOPPDocumenter
improved export of ms2 ground truth

 * all hits are exported in idXML scored/sorted by their intensity contribution
[TEST] extended MSSim test
[INTERNAL] move last definitions from header file
[TEST,INTERNAL] added test access getMS2Identifications before a simulation was performed

 * fixed segfault if getMS2Identifications but no simulation was performed
[FEATURE] cleanup of transform functions for mzML
[FEATURE] cleanup of transform functions for mzXML
[DOC] fix docu

fix error in the docu
Merge pull request #972 from hroest/fix/FileCleanup

Fix/file cleanup
Merge pull request #967 from aiche/feature/mssim-more-ground-truth-in-idXML

[FEATURE,TEST] mssim more ground truth in id xml
Merge pull request #966 from hroest/feature/ChainingConsumer

[FEATURE] chaining consumer