Update for Laravel 4.2.* & rcrowe/TwigBridge 0.6.*

* Updated for [laravel/framework 4.2.*](https://github.com/laravel/framework) 
* Updated for [rcrowe/TwigBridge 0.6.*](https://github.com/rcrowe/TwigBridge)
* Updated minimum PHP Version to 5.4 to stay aligned with laravel/framework
* src/Fojuth/Plupload/TwigExtension.php Had to be refactored for TwigBridge 0.6 changes

Upgrading to Laravel 4.2 required a bump to TwigBridge 0.6 due to other dependencies. I want to say 4.2 won't support 0.5 but I could be mistaken.

These changes are tested and working fine in my use case:

Laravel 4.2.*
TwigBridge 0.6.*

Ubuntu 14.04 (production server & local Homestead vagrant)
PHP 5.5.15RC1

**BC Breaking changes:** This PR will break anyone using Laravel 4.1.* and TwigBridge 0.5.*