- NKRO is used only when keyboard_protocol = 1(report)

This takes the last, reserved bit there, but doesn't necessitate
a revision to the magic number because it doesn't alter byte order.
Add reference to NKRO virtual dip-switch to documentation.

- Add action_util.c and remove action_oneshot.c
- Add oneshot_mods for MODS_ONESHOT
- Add weak_mods for MODS_KEY and MACRO
- weak_mods is cleared when layer switching

Add help text.
Add missing SLEEP_LED_ENABLE checks.

- Remove ACT_LAYER_BITOP

- Remove ACT_OVERLAY
- Rename ACT_KEYMAP to ACT_LAYER
- Add ACT_LAYER_BITOP

- NO_PRINT: disable print.h API(also disable debug.h)
- NO_DEBUG: disable debug.h API

- current_layer indicates active layer at the time
- default_layer indicates base layer
- default_layer is used when current_layer is 0
- with this LAYER_BIT action works as overlay even if
  default_layer varies other than layer 0.

- Fix keyboard_task() when matrix column size > 16
- Add clear_keyboard() in NKRO command to avoid stucking keys.
- Fix function name in print.c.

Fix: add wait for Power down command
Add ifdef of MOUSEKEY_ENABLE