add ictce/5.5.0 easyconfigs for Bowtie2, TopHat, GMap, HTSeq, Cufflinks

@JensTimmerman: please review, since I stole part of this from your `cufflinks` branch, and you have a need for some of these?

depends on #563 for the Python 2.7.6 ictce/5.5.0 easyconfig