add minimum samples requirement for modalities
make bootstrapped false by defailt
ix --> iloc for speed
add option to use fractions of cells for nmf
properly check for distributions if pandas series
separate out binned to assignments
add test for toy modalities assignments occuring properly
change minimum number of cells for modality calculation to be 50%
Merge branch 'fix_modalities'

* fix_modalities:
  change minimum number of cells for modality calculation to be 50%
  add test for toy modalities assignments occuring properly
  separate out binned to assignments
  properly check for distributions if pandas series
  add option to use fractions of cells for nmf
  ix --> iloc for speed
  make bootstrapped false by defailt
  add minimum samples requirement for modalities
Merged tidy_splicing, modalities changes