incremented batchglm requirement to 0.7.4

incremented batchglm dependency to 0.7.3

Merge pull request theislab#123 from theislab/tf2_compatibility

introduced numpy backend

incremented batchglm version requirement to 0.6.8

fixed bug in .mean of pairwise test

if data was csr_matrix, then _mean was still a matrix which broke summary dataframes.

incremented batchglm requirement to 0.6.6

incremented batchglm requirement to 0.6.5

updated gitignore

incremented batchglm requirement

added new batchglm version requirement to docs