* provide means to turn on RTP mode and set the amplitude
* new keycode HPT_CONT to turn RTP off/on
* introduce new keycodes HPT_CONI, and HPT_COND for Haptic Continuous Increase and Decrease
* support for continuous mode amplitude increase and decrease
* code cleanup
* update docs to reference new keycodes and functionality
* don't touch the keymaps
* add function prototypes
* add proper guards
* cleanup guards
* remove extra reserved