[FIX #806] ConsensusID

TOPP ConsensusID FileType idXML:
- after reading a peptide identification, sort their peptide hits with assignRanks()
- set the score type and the higherScoreBetter flag in the final peptide identifications before apply consensus

ConsensusID:
- ranked:
	- read the score_type information to write it into the output file
	- set higherScoreBetter = true, to recognize it easier that it should be true
	- setScoreType with Consensus_ranked instead of Consensus_average

- PEPMatrix_, PEPIons_: raise error if higher_better == true instead of false

Check if score type and higherScoreBetter are equal in all peptide identifications (average_, PEPMatrix_, PEPIons_):
move the check to the peptide identifications loop instead of the peptide hits loop, because only peptide information is needed for the check.

Test:
- ConsensusID_1: instead of average is ranked
- ConsensusID_4 (algorithm "PEPMatrix_"): test if the peptide hits are sorted

modified:   ../src/openms/source/ANALYSIS/ID/ConsensusID.cpp
modified:   ../src/tests/topp/CMakeLists.txt
modified:   ../src/tests/topp/ConsensusID_1_output.idXML
new file:   ../src/tests/topp/ConsensusID_4_input.idXML
new file:   ../src/tests/topp/ConsensusID_4_output.idXML
new file:   ../src/tests/topp/ConsensusID_4_parameters.ini
modified:   ../src/topp/ConsensusID.cpp
Merge branch 'develop' into fix-consensusid
Merge pull request #854 from PetraGutenbrunner/fix-consensusid

[FIX] ConsensusID doesn't sort peptide hits before processing (idXML)
[BUILD] added test for x!tandem version to enable tests only with newer versions of x!tandem
Merge pull request #863 from aiche/feature/tandem-version-check

[BUILD] added test for x!tandem version to enable tests only with newer ...
[FEATURE] improved purity computation
[FEATURE] adds puritystate struct to track current precursor and followup scan
[FIX] fixed some float compare warnings
[FEATURE,INTERNAL] added faster purity computation that works in a single linear scan
[INTERNAL] moved purity computation into separate method allowing computation on different spectra
[FIX,FEATRE] fixed computation of follow up scan and implemented purity computation based on Savitski et al. 2011

 * removed debug output
 * adapted test purity values, values where manually validated
[INTERNAL] code cleanup and some more documentation
[INTERNAL] improved handling of experiment end case