Proposed tweak for `slime-lisp-options'

Hi,

`slime-lisp-options' in slime.el uses `split-string' to parse the contents
of `inferior-lisp-program'

This fails if the lisp program is in a path with spaces in it (such as
executables in Windows).  Quoting does not help.

One could instead use split-string-and-unquote:

(split-string-and-unquote "\"c:/Program Files (x86)/clisp-2.49/clisp.exe\"
-E iso-8859-1")

   ("c:/Program Files (x86)/clisp-2.49/clisp.exe" "-E" "iso-8859-1")


Mirko