emacs: cleaned up mode's exit and do not start on non-ml files.
emacs: cleaned up mode's exit and do not start on non-ml files.

rgrinberg/merlin,dra27/merlin,ocaml/merlin,dra27/merlin,ocaml/merlin,rgrinberg/merlin,the-lambda-church/merlin,haselwarter/merlin,ocaml/merlin,fxfactorial/merlin,neojski/merlin,chriskonstad/merlin,haselwarter/merlin,fxfactorial/merlin,the-lambda-church/merlin,rgrinberg/merlin,ocaml/merlin,haselwarter/merlin,fxfactorial/merlin,the-lambda-church/merlin,dra27/merlin,neojski/merlin,chambart/merlin,neojski/merlin,haselwarter/merlin,chambart/merlin,chriskonstad/merlin,fxfactorial/merlin,chambart/merlin,neojski/merlin,dra27/merlin,rgrinberg/merlin,chambart/merlin