Reworked entity creation in most cases - it's done one at a time now rather
than all at once. This allows us to have more entities than the previous limit
of 130, and also looks a little nicer.
Folders and files now pop into existence instantly instead of sliding - makes
navigation easier. Depots still slide because there typically aren't as many
of them (okay, I might eventually make them pop too, but I'm tired now).
Revisions slide because it looks really cool - like a waterfall pouring out of
the file.
The upper limit to entities is now due to the "visible entity packet" thing,
which I'm certain I have no control over - it's as high as it can possibly be
right now.