Paged layout, busy dot.

After poking around at jjmpeg a bit this morning, I played a bit more with ReaderZ. First I added an animated 'busy' icon for when the reader is busy, and moved the epub html loader to another thread so it animates. It's ugly, but it works. I simplified the use of the event manager as well.

Then I redesigned the BlockLayout code in CSZ so that I could sub-class it to create a paged media layout. It isn't 'conformant' by any stretch, and has a bug with tall images, but at least it forces lines to align to a new page once they've overflowed the viewport.

During this I realised I probably wont be able to get away with a single-pass for the layout. e.g. if you have an auto-sized box, it's size depends on things like the size of floats and the lineboxes inside of it. But you have to lay these all out before you can determine what it is, and then must lay them out again afterwards once you've determined the real size you're working with (also required for things like text-align). I might have to lay out individual words instead so then the second layout can be fast as well as letting the layout be handled separately from the text object.