[slim-vim] Slim-vim is trucking along nicely

[Brad Beveridge]

After Larry fixed the socket patch I got all enthused about actual
slim-vim code again and got to work.
Here is the change log
   * Vast improvements, almost usable now.
   * Added a buffer-util.lisp file, largely cribbed from Larry's ECL REPL code.
   * Split the old ABCL code out into a new file "old-slime.lisp", but
probably the code in there isn't any good anymore.
   * Renamed some of the buffer names
   * Put some more notes into the notes file
   * Added more keymappings, they are generally close to what Slime's are
   * Added more functionality
    - <C-Shift-x> slime-eval-last-expression
    - <C-x>  slime-eval-defun
    - slime-compile-file
   * We now handle debug events in a more reasonable way
   * Added lots of TODO statements
   * Changed the way that swank-null defines its exports

I've tried to closely match the Slime key bindings, but dropped
extraneous key presses where I could.

As always, feedback is more than welcome.

Cheers
Brad