Save feature data with a datapackage
change default colors to Dark2 instead of Set1
fix loading of species data, and make all resource dfs kwargs
plot pooled and outliers  on PCA :)
don't try to plot pooled, outliers on PCA if the dataframe is empty
Make PCA figure smaller (and thus text bigger)
fix makefile for new test dir location
Change default sample subset to be calculated in MetaData
some pep8 fixes
add global variable for minimum feature subset size
add columns to ignore in the feature data when creating subsets (e.g. gencode_id, etc)
update example data for testing to shalek2013 because it loads super fast
add datapackage for shalek2013
remove thresholded property from ExpressionData since its in BaseData
tests pass!!