More explicit variable name, built through builder

Instead of calling the method in the body of the code
Multiple condition testing and SamplesFile fully..

tested.
Validator tests implemented. All passing.

Also defined several more RNASeq types
Continuing to implement exception system

More tests added
Minor tidying up. Added Rscript test
RScript test implemented. Passing
R script job submission tested. Passing.
Minor correction on RScriptJob.t
Merge pull request #49 from js21/master

88% test coverage for DeSeq wrapper