Remove threading from GE frame reader
Implement "hexrd cache-frames" that saves the coo_matrix frames in a .npz file
Add multiprocessing.freeze_support in the hexrd cli

This fix allows fit-grains to work with multiprocessing on
Windows. find-orientations still produces an error.
Passing values by global variables not supported by multiprocessing

While this generally works on linux and osx, where multiprocessing
uses fork, this does not work on windows. This removes the
global variable passing for the inner function called by
find-orientations
Using "x is 1" or similar is not portable/guaranteed to work

This change replaces "is" by "==" and "is not" by != in these
cases.
On Windows, require setuptools and make a hexrd.exe entry point

This allows one to call hexrd from the windows command line as
just "hexrd ..."
saves cahced frames to analysis_dir
tweaks to conda recipe
Merge branch 'win_multiprocess'