Add code that performs photoRec differential expression analysis w/r/t gType and simplified devStage (using only the first and last levels)
Merge branch 'master' of https://github.com/jennybc/stat540_2014

# By Dean Attali
# Via Dean Attali (1) and Gloria Li (1)
* 'master' of https://github.com/jennybc/stat540_2014:
  tiny fix to make description and command match