Bump version to 2.1.
UPdate fdroid data file.
Check in screen shots.
Tag 2.0 release now.
Update release date and revision for the 2.0 release now.
Add separate help menu texts for Tri-Angulo.
Don't mention 'simple mode' since it is the only mode (for now at least).
Add some ideas to TODO list.
Replace on-top drawing pattern with a different one.
Update release notes.