fixing issue 54, refactoring -
issue caused by storing the bitmaps in the cache with inconsistent bitmap height/width due to scaling (or not scaling), fixed by removing the height/width when adding the url as the key
refactoring loader task to take a imagewrapper instead of an imageview as it was needlessly recreate the imagewrapper from the imageview but...
the imagewrapper causes issues when used as a weakreference, so for now it's a final field but I need to make sure it isn't leaking