Added a make_filepath method to Data aggregator.
Added a make_filepath method to Data aggregator.

It's rather tedious to build paths with os.path.join using the
Data.location method every time I want to save a plot. This method cuts
out the middleman.

datreant/datreant,datreant/datreant.core,datreant/datreant,datreant/datreant.core,datreant/datreant.data,dotsdl/datreant,andreabedini/datreant