Plane: ready for 2.75 release
Copter: fixed HIL build
BoardLEDs: all leds off during init
BattMonitor: add @Increment to CAPACITY description
Plane: add @Increment to battery failsafe descriptions
Copter: add @Increment to battery failsafe descriptions
Copter: add ANGLE_RATE_MAX param

Limits the maximum rotation rate requested by the angle controller which
is used in stabilize, loiter, rtl and auto flight modes
AP_Airspeed: fixed I2C semaphore handling for I2C airspeed

this affects MS4525DO on APM2
HAL_AVR: back to 8MHz SPI for MS5611 and MPU6k
HAL_AVR: changed to 16 byte bulk transfer on SPI0
AP_InertialSensor: try to lower SPI bus speed on errors
AP_InertialSensor: automatically lower bus speed on mpu6k bad reads
AP_Math: fixed zero function for integer vectors
AP_InertialSensor: detect bad MPU6000 SPI transactions and lower bus speed

this uses bad data or bad INT_STATUS values from the MPU6000 to detect
the sensor running too fast and lower bus speed
AP_Baro: start MS5611 at high speed
HAL_AVR: run MS5611 with dual speeds on APM2
Rover: report INS health
Copter: report INS health
Plane: report INS and airspeed health
AP_Airspeed: added healthy() API