ess-kill-buffer-and-go modfied to not restart R if it is not already run...

The behaviour of ess-kill-buffer-and-go is unexpected when you're trying to close a help file after R has already been closed. As is, this will call ess-switch-to-ESS, which will in turn call ess-force-buffer-current. This will restart the R process, just as you're trying to kill an errant help window.

This pull request modifes the behaviour of ess-kill-buffer-and-go to skip the call to ess-swtich-to-ESS if R is not running. There may be other, cleaner fixes, but this seems to work.