New NMD branch.

Will start keeping all the specific run files in this new branch.
20K/0/4x/post.nmd.npy

new specED data.
Updated nmd.py

nmd.py now contains info on the box size for thermal conductivity
calc.
Commit moving onto silicon.

Since nmd is too expensive I am essentially abandoning it for this project. ALD is sufficient.
Moving onto silicon.
Merge branch 'master' of https://github.com/kparrish/isostrain

Changed readme