Allow symfony 2.3 and greater

Also run travis tests on symfony 2.2
improve phpcr loader doc
Merge pull request #177 from liip/phpcr-loader-doc

improve phpcr loader doc
Merge pull request #176 from tommygnr/symfony2.3

Allow symfony 2.3 and greater
fixed documentation for getting the browserPath when generating thumbs from a controller
fix broken tests on windows
fixed identation
Merge pull request #178 from leberknecht/master

Small documentation fix for getting browserPath for a thumb from controller
Remove error suppression, add more verbose skip message
fix doc of CacheManager::resolve to not lie
Merge pull request #186 from liip/fix-cache-phpdoc

fix doc of CacheManager::resolve to not lie
add CacheResolver
add documentation about the CacheResolver
Merge pull request #179 from kevarch/tests/windows-support

fix broken tests on windows
Merge pull request #184 from havvg/feature/cache-resolver

add CacheResolver