Added slice_regions_matrix.py and merge_replicates.py. Imprved differential_expression.py and made it compatible with Python 3 and R 3.4
Added slice_regions_matrix.py and merge_replicates.py. Imprved differential_expression.py and made it compatible with Python 3 and R 3.4

SpatialTranscriptomicsResearch/st_analysis,jfnavarro/st_analysis