merlin-imenu: require subr-x
merlin-imenu: require subr-x

Necessary to use string-trim function (introduce in Emacs 24.4).

the-lambda-church/merlin,rgrinberg/merlin,the-lambda-church/merlin,rgrinberg/merlin,dra27/merlin,ocaml/merlin,ocaml/merlin,rgrinberg/merlin,rgrinberg/merlin,dra27/merlin,dra27/merlin,ocaml/merlin,dra27/merlin,ocaml/merlin,the-lambda-church/merlin