Store/Load PDF

[MorganAskins]

When reading in a datafile to build a model (say root to dataframe), the computational task of reading in the data then generating the PDF can be long (sometimes longer than fitting the model to data). Given this, we should store this intermediate step into a cache file with a unique hash. When the program is run again, it checks if it should re-evaluate the PDF based on this hash or if it can simply begin at the intermediate step.