Emacs inferior mode fixes

[Brian T Rice]

I made a couple of fixes to Slate's emacs mode tonight which make it
nicer to use:

The Slate inferior emacs mode will now not ask for the command to run
unless it hasn't already been specified somehow.

Also, the evaluate-region command (ctrl-c e) that works on the current
selection now works properly, and will start a Slate process for you if
there isn't one already;  although this is not recommended, since most
expressions depend on the libraries being loaded, so you may get some
surprises.

-- 
Brian T. Rice
LOGOS Research and Development
http://tunes.org/~water/