Merge pull request #267 from FCP-INDI/0.3.2_release

Removed potential error while trying to read average_snr_file.txt.
Removed potential error while trying to read average_snr_file.txt.
Updated developer documentation - no functionality changed.
Updated version number to 0.3.2.1 to reflect fixes to QC.
Merge branch 'master' of https://github.com/FCP-INDI/C-PAC