Auto compilation of javascript

First version of javascript compilation.

Some things can be improved for sure but for a first try, I think it's quite ok.

So let's go through its usage, if you want your file to be compiled by Beluga, you have to put it to the js folder within your module.

Then, your file will be called and compile only and only if you have a method prototyped 

`public static function init()`

It's your entry point for your class and your javascript code. You can have multiple files with the init method and every files without this method won't be compiled automatically, thus, you have to import it yourself from one of your files already included.

Not sure if everything is clear, but you can just go into `beluga/module/account/js/Javascript.hx` to see it in action.

A file called `beluga.js` will be made and put into the `OUTPUT_FOLDER/js`. Just make sure to include it somewhere in your HTML and you will be all set.

fixes #150