3.4/develop

Fully embraced the composer way of doing things, added requirement of PHP 5.4+, and added some fancy new 5.4 stuff.
I believe we should make it the easiest for the developer to have the official modules. It should be suggested in composer and listed-but-commented-out in boostrap.

As a side note, now I think Kohana modules should go to `vendor` just like `kohana/core`. It will be kind of strange to see the system path in `vendor` and other modules in `modules`. Maybe we should deprecate Composer type `kohana-module`

I now understand @Zeelot here: Zeelot/kohana-media#16