Merge branch 'tweaking-readme'
Merge branch 'new-thumb-diagram'
Merge branch 'case'
Merge remote-tracking branch 'technomancy/master'

Update so that I have all the latest changes.
OpenSCAD design with (optional) 2 thumb keys per hand.
Merge pull request #7 from ckhroulev/two-thumb-keys

OpenSCAD design: allow choosing between 1 and 2 thumb keys for each hand