Split up fixtures so we always have a few SAME users every time
    Usernames: admin, user, owner
    Password: secret
Added Image entity
Updated readme how to fix autogenerated entities
Updated Image entity
More tweaks on uploading related classes/entities
Updated Image and Book entities and related fixtures
Added UploadManager
Added Imagine library
Added helper controller for image uploads
Renamed var for more clarity
Fixed ApiBundle's action loading logic
    Now it is possible to override generic CRUD actions with per-resource specialized CRUD actions
Cleaned up book details action
Book details now return image
Imagine lib requires GD installed on server
Book details now return proper links for images
Added user image filter configurations
Make transformed image URLs nicer
Replaced user read generic action with custom one
Merge remote-tracking branch 'remotes/origin/image_upload'
    Closes #17 and partially #14