GratRevBarLoader.byTrigger() added
pf arg removed from GRL.getByTrigger()
RasterUtil.meanSpikeVectors() created
* RasterUtil.rates() rewritten to use it
RasterUtil.responses() created, finds best stims
Misc/grk2 added (originally by Jamie, but I think I made some changes a while ago)
GratRev.plotBestStimuli() created, documented