Merge bundles (close #3)

 Merge composer.json

Merge configuration

Merge PHPUnit config

Create separate installation doc

Change namespace to FOS

Support Symfony 2.4 and drop 2.1/2.2 support

Remove cURL check

Fix search/replace mistake

Fix typo

Make contributors homepage URL forwards-compatible
Merge branch 'merge-bundles' of github.com:ddeboer/FOSHttpCacheBundle into merge-bundles