Update app icon
Make CancelableAction<T> provide a canceled() function query able in the action

- this is so that long running actions might bail if canceled() ever returns true during their execution.
- add result:T? property which is assigned when the action completes
Fix async saves of matches to gallery store
Fix bug that allowed last player of a match to continue drawing while the final presented match was showing.
Improve match export

- add SQUIZIT watermark
- drop the paper background texture
Delete unused icon graphics