Consistently register user defaults in +initialize.

Fixes a problem where dock countdown was not visible because it was reading nil = false (at least on 10.8).
Improve dock countdown display.

Draw a more standard-looking shadow and use rounded ends on the frame to match icon badge appearance.

Try to use a more retina-compatible drawing method (the documentation recommends it, but I'm not sure it actually helps) on 10.8+.
Remove now-redundant NSValueTransformer registration.
Update documentation for 1.1.

Finally!