Merge branch 'master' into develop

* master: (25 commits)
  add doctrine/cache to require-dev
  add test on cyrillic filename for FileSystemLoader
  Update filters.md
  Add comment for image parameter in watermark filter configuration example
  Update doc
  Fix typo
  Add upscale filter
  Set ContentType of AWS cache object
  deprecate the phpcr loader as CmfMediaBundle provides a better one now.
  fix missing filename in exception
  Corrected aws-sdk-php link
  add AwsS3Resolver for new SDK version
  Add simple documentation
  Watermark loader
  Update dependency 'imagine/imagine' to 0.5.*
  fix E_NOTICE "Undefined index: mode"
  small fixes on Thumbnail docs
  added documentation on inset and outbound modes of thumbnail filter Documentation (issue #207)
  also test SF 2.3 and PHP 5.5
  Add link filter
  ...
[resolver] remove request from resolve method.