General cleanup based on the pull request from muggenhor
Reformatting.
First steps to supporting GPS
More changes.
Merge remote-tracking branch 'upstream/master' into hott_v2
Add some GPS data to telemetry message.
gpio_led app added
Use work_queue instead of thread
Merge branch 'master' into gpio_led
GPS support - mostly working.
Merged new repository layout from PX4/Firmware
Merge branch 'master' into gpio_led
Added GPIO_EXT1/GPIO_EXT2 selection.
Code style fixed
Initial work of so3 nonlinear complementary filter
I missed to add build command
Fixed few minor bug
I do not know why roll angle is not correct. But system looks okay
Roll pitch yaw should be verified again
To use freeIMU processing visualization tool, I have implemented float number transmission over uart (default /dev/ttyS2, 115200)
But this not tested yet. I should.