a bunch of changes, mainly to get automated grain pulling running

* started framework for reading from bz2 archives in detector readers
* lots of fixes to fitting -- added a wrapper for grain fitting
* modified material to take in more kwargs to initialize
* fixed angularDifference in transforms (was giving incorrect results for x + 2npi for n > 1)
* added reg_grid_indices to transforms
* modified paintGrid_cmd to do proper com offsets in fiber generation