Reorganized matlab code for simplicity + change to pydata load

1. Created new folders and moved relevant files into them
private: all necessary subfunctions to calculate Iidf
data: precomputed datasets
figures: self explanatory
unused: deprecated stuff. Mostly old serial code

2. Changed pydata2.m to a mat file -- saves on space, and allows us to
load it from the data directory via the "load" command, rather than
running pydata2.m as a script