Reduce memory usage and Speed up initialization

[razorstorm]

Suggestion: In background's constructor, load from resources, and then if doesnt exist, build the bitmap and then save to resources.

http://stackoverflow.com/questions/3648942/dynamic-resource-loading-android

http://stackoverflow.com/questions/4539630/how-do-i-check-to-see-if-a-resource-exists-in-android

http://stackoverflow.com/questions/649154/android-bitmap-save-to-location

[razorstorm]

Memory is good enough. Initialization doesn't seem to be able to be sped up any more.