* Remove chording as it is not documented, not used, and needs work.
* Make Leader Key an optional feature.
* Switch from `PREVENT_STUCK_MODIFIERS` to `STRICT_LAYER_RELEASE`
* Remove `#define PREVENT_STUCK_MODIFIERS` from keymaps.
* redo make args to use colons, better folder structuring system [skip ci]
* don't put spaces after statements - hard lessons in makefile development
* fix-up some other rules.mk
* give travis a chance
* reset KEYMAPS variable
* start converting keyboards to new system
* try making all with travis
* redo make args to use colons, better folder structuring system [skip ci]
* don't put spaces after statements - hard lessons in makefile development
* fix-up some other rules.mk
* give travis a chance
* reset KEYMAPS variable
* start converting keyboards to new system
* try making all with travis
* start to update readmes and keyboards
* look in keyboard directories for board.mk
* update visualizer rules
* fix up some other keyboards/keymaps
* fix arm board ld includes
* fix board rules
* fix up remaining keyboards
* reset layout variable
* reset keyboard_layouts
* fix remainging keymaps/boards
* update readmes, docs
* add note to makefile error
* update readmes
* remove planck keymap warnings
* update references and docs
* test out tarvis build stages
* don't use stages for now
* don't use stages for now
