Integrate mg-common

[markmcdowall]

Within the tools directory of mg-process-fastq there are common tool set modules called bam_utils.py and common.py. As part of the course these were extracted into a separate repo called mg-common. These are a duplicate of what is in the mg-process-fastq module.

The tools will need updating with what is in the mg-process-fastq repo, but they should be very close to each other.