* 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.
This is a place for users to put code that they might use between keyboards. If you build the keymap mine, /users/mine/rules.mk will be included in your build, and /users/mine/ will be in your path - keep these things in mind when naming your files and referencing them from other places.