Enhancement to auto complete current path

Enhancement to auto complete current path, https://github.com/FredrikNoren/ungit/issues/37

Uses custom jquery-ui and get rest API to get all directories in current path and allow users to select on the go.

![screen shot 2013-08-27 at 2 41 59 pm](https://f.cloud.github.com/assets/5281068/1045188/a8ef1e0c-1020-11e3-824f-c5f4eba918af.png)