Provide a way to check MuTect's version. However due to an issue,
it reports the GATK version it is based on instead: until this is
fixed, we use a hack knowing that 1.1.4 is based on GATK 2.2 and
1.1.5 on GATK 2.7.
Ensure that only MuTect 1.1.5 or higher is allowed to run
Remove hack for MuTect errors, not needed anymore with 1.1.5
Only use cached MuTect version
Use LooseVersion from distutils to ensure a better version check
Merge pull request #104 from lbeltrame/mutect-version-fix

Ensure only MuTect 1.1.5+ is used when doing tumor analysis