Asobu 0.1.1

Give Asobu an icon, an installer splash, and a dotted data folder

The launcher had no icon at all: Explorer, the taskbar and Alt-Tab all showed a
generic one. assets/make-brand-assets.py draws the mark the sidebar already
draws -- same rounded square, same offset play triangle, same accent -- at every
size Windows asks for, so the icon cannot drift from the app it belongs to.

The same script draws the installer's splash. Velopack's setup is one-click by
design, with no wizard to design: what it does show is a picture, so that is
where the welcome starts. Dark, pink, the mark and the name, with a halo that
breathes on a sine over the frame count so the loop has no seam -- an install
lasts a few seconds and the image is shown throughout, so anything that
restarted visibly would blink at whoever is watching it.

Data moves from %AppData%\Asobu to %AppData%.asobu, next to .minecraft and by
the same convention. An existing folder is renamed rather than left behind, and
a folder something still holds open is used where it lies rather than being
abandoned for an empty one.

ResolveIn takes the roaming folder as an argument so this is testable. It was
not before, and the test that appeared to cover it set the APPDATA variable --
which Environment.GetFolderPath ignores, so the test read the real profile and
proved nothing about the code.