Remove Preload-Experiment
Preloading images from /images/
Fixes off by one error when preloading

(non critical)
Actually invoke prefechting.
Reverse preloading order when preloading back.
Added ProgressCanvas which shows loaded images
Handling Preload-Errors
Using default image-Source.
Merge pull request #29 from MaPePeR/my-preload

Preloading Frames and storing them for later use.