*use BSGenome and Bioc dbSNP objects instead of downloading from UCSC.

*globals function needs to set elements in the list returned by
 options() instead of using the globals() fun. Other wise
 HTSeqGenieBase and gmapR will both have exported globals() functions

*HTSeqGenieBase needs to depend on gmapR and not contain now-redundant
 code. To to this, HTSeqGenieBase::globals() needs to have entries
 removed now in gmapR::globals()

*configureGmapR.R calls buildGmapIndex, buildGmapDbSNPIndex, and
buildRefseqSpliceSites. These are high-level functions that obtain
hg19 data and call more generalized functions. These high-level
functions belong in HTSeqGenieBase.