Added a number of new wrappers and extended samtools, all for the coming bamEvaluateStep class
Added BamEvaluateStep class which should replace both SampleBamStep and LibraryComplexityStep classes.
Minor change to ensure getPath can default to no path.  This allows having an executable on the execution path.
Fleshed out a few paths and added some expected version.  While I don't anticipate ever enforcing the version, this at least documents what versions are currently expected.