Added vagrant and gulp task for minification

Hi. I've added a Vagrant config and Gulp task to build minified releases (~9KB).

To use vagrant you must install the latest versions of ruby, virtualbox and vagrant. Then call `vagrant up` in the project folder (it will create a virtual machine and install needed packages in it).
After that call `vagrant ssh` to login in it, and `cd /vagrant` (mounted project folder in the virtual machine.

Finally, run `npm install` (it will install needed packages for building you project) and `gulp build` to create minified version of autoComplt.

Alternatively, if you don't want to use a vagrant, `nodejs` and `gulp` must be installed globally in your system, and you can run `npm install` and `gulp build` on the spot.

Don't forget to build new minified versions for every release.