Return value of the NBsample() method changed to a list

MAplot() method added

Support of edgeR_2.7

Packaging for release from CRAN is underway.

The paper describing TbT (TMM-baySeq-TMM) pipeline is published in 
Algorithms for Molecular Biology 2012 Apr 5;7(1):5. PMID: 22475125.
You can read the paper at
http://www.almob.org/content/7/1/5
