Remove backup ImageProcessingFunctions 

* old definitions were obscuring some modified functions
use try(source()) so R doesn't stop when it fails with Dyakuba but keeps running
this is a fix of the default image output (square) so brains images are now generated with proper side ratio
fix: neuropilmask has to be defined BEFORE it is used by sapply and not AFTER. and commented out the calculation of absolute volumes for the moment
RegionPerm does now what it is supposed to do: it calculates fractional volumes for each np_region for each species. it further calculates whether these fractional volumes differ (nb: could be both rel greater or smaller) from those in Dmel. and it calculates their absolute volumes (i.e. rel*8).
fix: only takes files into account that END in .nrrd. this is to exclude the ones which have stitched names that contain nerd.