Remove show_patch, replace with renorm.

Removed show_patch.m since it was too easy to abuse it.  Replaced it with
renorm.m, which renormalizes a matrix to a specified range (default [0,
1]).  This can be used like show_patch with "imshow(uint8(renorm(x, 0,
255))))", which I believe is more explicit, and not much more to type.
Removed some commented code I forgot to delete