add docstring
Merge branch 'master' of github.com:YeoLab/flotilla

* 'master' of github.com:YeoLab/flotilla:
  correctly fail if there are no pooled samples for a group
  version bump to 0.2.5dev
Add summary docstring
initial try at creating an option for interactively coloring samples
cast index to list
groupby, not label_to_color
set default color_samples_by
check if color_samples_by is the default
add test for color_samples_by
Merge pull request #220 from YeoLab/interactive_pca_choose_colors

Color samples by different columns in metadata