Kept forgetting that find_brights is for imageJ

	renamed:    find_brights.txt -> find_brights.imj
Cleanup for track plotting:

 - nicer markers (transparency, no outline)
 - square aspect ratio
 - zoom in to within 10 pixels of outermost particles

	modified:   tracks.py
Fixed several figures for writing.

 - Merged subplots of g(r) and g_4(r)
 - Gave up on icon insertion in order_params plot,
   inserting later using latex in the writing.git repo

	modified:   equilibrium.ipynb