Merge low_quality_cells into develop

Merge branch 'develop' into umi_quality2

# Conflicts:
#	CHANGELOG.md
#	Estimation/BamProcessing/BamProcessor.h
#	Estimation/BamProcessing/FilteringBamProcessor.h
#	README.md
#	dropestr/NAMESPACE
#	dropestr/R/cell_number.R
#	dropestr/man/ScorePipelineCells.Rd
#	dropestr/src/utils.cpp

Float quality

Moved quality threshold to config

Removed test hardcode values