Added queue to mpu6k driver
Merge branch 'master' into mpu6k_queue
Add some more useful methods to the ringbuffer class.
Try to save our sanity a bit and use the generic ringbuffer class rather than re-implementing the wheel.
Fixed driver test / direct read, looks good
Added rate limit in sensors app. Just pending accel filters now
mathlib: added LowPassFilter2p object

used in gyro and accel drivers for better filtering
Enabled mathlib
Merge branch 'master' into mpu6k_queue
Merge branch 'master' of github.com:PX4/Firmware into mpu6k_queue
Equipped MPU6k driver with Butterworth for accel and gyro
Increased MPU6K poll and sampling rate to 1 KHz
Made sensors startup routine more flexible
mpu6000: set the default DLFP filter to 42Hz

this allows for apps to ask for slightly higher filters with the
software filter and not have it completely ruined by the on-chip DLPF
Merge branch 'mpu6k_queue' of github.com:PX4/Firmware