Copied ImageManager from MMDb. Enables asynchronous load of images (#2) through a separate type.
Renamed ImageLoadManager to DataLoadManager, which will handle asynchronous load of arbitrary data.
This applies to issue #2.
DataLoadManager is now abstractly defined to load from TKey type to TValue type.
Moved the two nested classes DataLoader and DataLoadState to seperate files (not nested). Removed the LoaderCollection class.
Dataloader thread loop runs infinitely and can only stop when dequeing.
Added icons for loading.
Implemented alpha blending for images loaded into ImageBox (issue #2).
Implemented asynchronous (and synchronous) load of images using an imagebox.
Added LoadingIcon type that handles drawing of serveral different spinning load-icons.
Added loader icon to ImageBox - displayed when images are loaded in another thread.
Keyboard messages are only sent when a keyboard control is selected.
Merge branch 'ImageLoading'