[Sf2SK] Updated app/SymfonyRequirements.php
[Sf2SK] Ignoring tmp folder & shell scripts in root folder
[Sf2SK] Updated testing tools: PHPUnit 4.4 & CodeSniffer to 2.*
[Sf2SK] Vagrant: Using trusty32-phpdev-20141220
[Sf2SK] Updated README.md to reflect usage of Symfony Standard Edition 2.6.1
[Sf2SK] Using symfony/assetic-bundle ~2.4 due to incompatibility with assetic 1.2