feat: add ThumbCluster keycodes and update layout configurations. Thi…

[domelqq]

Some of the new type of matrix layouts are using thumb cluster section to put there one or two letters.
Hands down promethium is such one
https://www.reddit.com/r/KeyboardLayouts/comments/1g66ivi/hands_down_promethium_snth_meets_hd_silverengram/
With current configuration letter R is not in the matrix layout and because of that is also excluded from lessons.

PR adds two thumb buttons on each side that any of the matrix layouts can later use it.
With letter in thumb cluster emulation does not make sense as there is no fifth row on standard keyboard.

With the change R is correctly added to lessons.
Thanks - great tool

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
packages/keybr-keyboard-io/lib/keys.ts	0% smaller
packages/keybr-keyboard/lib/geometry/matrix.ts	0% smaller
packages/keybr-keyboard/lib/keycode.ts	0% smaller
packages/keybr-keyboard/lib/layout.ts	0% smaller
packages/keybr-keyboard/lib/layout/en_hands_down_promethium.ts	0% smaller

[aradzie]

Something is not right with the tests, they are failing.
I'll take a closer look tomorrow (I live in Europe) and then will suggest fixes to your PR or merge it as is and fix the tests myself.
Anyway, thanks for your contribution!

[domelqq]

Something is not right with the tests, they are failing. I'll take a closer look tomorrow (I live in Europe) and then will suggest fixes to your PR or merge it as is and fix the tests myself. Anyway, thanks for your contribution!

Yeah its late here. Cheers from Poland :)

[aradzie]

I updated the web site with your changes.
Thanks again!

[domelqq]

Thanks :)