[DRAFT PATCH] emacs: Eliminate buffer invisibility specs from show and wash

[David Bremner]

Austin Clements <amdragon at MIT.EDU> writes:

> Previously, all visibility in show buffers for headers, message
> bodies, and washed text was specified by generating one or more
> symbols for each region and creating overlays with their 'invisible
> property set to carefully crafted combinations of these symbols.
> Visibility was controlled not by modifying the overlays directly, but
> by adding and removing the generated symbols from a gigantic buffer
> invisibilty spec.

Pushed. 

d