Let CodeMirror.showHint return true if it has hints

If e.g. javascript hint does not match any known - use "anyword" hints:

CodeMirror.commands.autocomplete = function (cm) {
	if (!CodeMirror.showHint(cm, CodeMirror.hint.javascript))
		CodeMirror.showHint(cm, CodeMirror.hint.anyword);
};