fix #320 bug ui.keyCode enum
define escapeRegex function

https://github.com/jquery/jquery-ui/blob/master/ui/jquery.ui.autocomplete.js#L567
removing undeclared variable
Merge pull request #321 from AbraaoAlves/master

Fix compile error's
Merge branch 'master' of https://github.com/borisyankov/DefinitelyTyped