Build script

This set the build script and the directories structure.

We have 3 directories:

* `resources/` = directory used to push resources in Transifex
* `languages/` = directory used to pull translations from Transifex
* `packages/` = language packages

Let us not commit changes within `resources/` and `languages/`, because they are already being held elsewhere (WooCommerce Core and Transifex)

In grunt we have 2 two main tasks:

* `grunt compile` = Gets the Transifex translations, compiles the .mo files and generates zip files
* `grunt resources` = Gets the WooCommerce core .pot files and pushes on Transifex


Anyway, just compile the new version of the translation and create a tag. o/
That everything perfect for WooCommerce download the translation package.