Do the final utility refactor, placing custom views into a .ui
submodule and the general utils into a new .util module. This
system seems to stick well.
Add a nice elevation effect to queue dragging operations. This has no
purpose outside of looking nicer. Luckily it doesn't effect queue
behavior at all.
Move the AndroidUtils file into the root Auxio directory, renaming it
to AuxioUtils as well. This also changes some methods to be extension
methods instead of argument functions.
