Added ModificationInterface#resizeKeepAspect()
Added a bunch of documentation

Documented the materialization interface

Documented Hitch\Storage\File

Documented Hitch\Storage\StorageInterface

Documented Hitch\Image

Documented Hitch\Modification\GD

Documented Hitch\Modification\ModificationInterface

Documented Hitch\Uploader
Added materialization method
Initial draft of refactor
Added type detection
Added image loading
Added resource swapping
Added ability to get contents of a GDImage
Added type support to #getContents()
Image now reports proper dimensions
Added Hitch\Image\Image tests
Remove old classes
Uploader works with images now
Fixed GD modifier
Fixed Hitch\Storage\File
Initial draft of documentation