move some MESSAGE files to installed docs

["Jeremy C. Reed" <reed%reedmedia.net@localhost>]

Various MESSAGE (+DISPLAY) files aren't very important for immediate use 
of their packages.  Maybe we should move these MESSAGES to files/README 
or something like that and just install them.

The guide documents:

   ``This file is displayed after installation of the package. Useful 
   for things like legal notices on almost-free software and hints for 
   updating config files after installing modules for apache, PHP etc.''

I didn't realize there were legal notices, but now I saw devel/idiff as 
one example. Maybe they should be listed using the license framework 
instead.

What prompted this email was devel/scmcvs/MESSAGE which maybe is not to 
important to display during install.

Any thoughts on this?