ivory-px4-hw: continue filling out ms5611 driver
ivory-px4-hw: create test for ms5611 driver
create test app bsp-ms5611-test
ivory-bsp-stm32f4: fix typo bug in i2c2 definition!
flight: update to use statemachine Time units
ivory-px4-hw: IOAR motor control uses correct statemachine Time units

this probably explains why it behaved less well on boot
the second time around, and also perhaps why we were losing a lot
of bytes due to ISRs constantly going off
ivory-px4-hw: ms5611 test reads prom properly when given spec time to reset
ivory-bsp-stm32f4: i2c peripheral driver bugfixes

- send stop during error only when required
- do not loop forever in sendStop or sendStop: limit
  to an arbitrary number of iterations (16).
- disable debug pins
ivory-px4-hw: complete init sequence for ms5611
ivory-px4-hw: standalone ms5611 driver reads work