* Added callbacks to one shot modifier changes
* Altered signature of callback functions
* Reordered the callback methods, shortened brief documentation
* Added One Shot Modifier callback documentation
* First attempt at unit tests
* Revert "First attempt at unit tests"
This reverts commit 5ec21a7822.
* Simplified oneshot function implementations
* Made clear_oneshot_locked_mods to be conform action_util.h, adhering to the (void) signature
* Made used datatypes for oneshot mods consistently unsigned integers
* Corrected callback to call clear callback when clear_oneshot_locked_mods is invoked
* Simplified oneshot equals statements
* Corrected return type and signature of get and set oneshot locked mods
* Consolidated one shot callbacks, added initial layer callback version
* Fixed non-updating one shot layer variable after timeout or other clear, added code comments
* Added better one shot key docs
This commit is mostly a cherry-pick from `ahtn` at
https://github.com/tmk/tmk_keyboard/pull/255.
These are the changes:
* Adds ACTION_LAYER_ONESHOT
* Adds ONESHOT_TAP_TOGGLE
* Mentions sticky keys in the docs on oneshot.
- new macro_mods bit field for mods applied by macros
- weak_mods now only used for ACT_{L,R}MODS (i.e. LSFT, RSFT, LCTL etc.)
- clear the _weak_ mods on every key *pressed* such that LSFT etc.
can no more interfere with the next key
