Remove useless definiition
Made offsets explicitly int32_t
Threshold is now unsigned.

Updated tests accordingly.
Made tons of types more explicitly signed/sized

Accel:
- accel_start_record_gesture takes a uint16_t *gesture
- accel_end_record_gesture takes a uint16_t *gesture

Moving_avg:
- wbuf_len is now a uint16_t

Updated pebble sample accordingly
updated phony targets
Added more compilation flags

-Wincompatible-pointer-types
-Wtype-limits -Werror=type-limits