Denovo motif discovery

The command chrombpnet modisco_motifs will soon be deprecated! please use the command directly from the tfmodisco-lite repo. For ChromBPNet releases <=v0.1.3 the -n seqlets has been hardcoded to 50000, and not functioning as expected. If you wanted to run it with 1000000 seqlets it was not running properly.

To do motif discovery please refer to tfmodisco-literepo https://github.com/jmschrei/tfmodisco-lite/