Moved yaw correction to its proper location (between velocity PID output and before pitch/roll PID input).
Eliminated leftover graph_add_node_SpecificTypeHere() functions.

Added define for USE_LIDAR. Lidar is still polled and the node is updated, but it is not used for altitude control by default.

Allowing throttle to be down during autonomous.

Properly setting sampling time for altitude PID with LiDAR. Fixed HW impl tests for lidar_t changes.

Refactored velocity configuration in control algorithm. Made default PID constants the good ones. Corrected the velocity sign. There might be sign errors with the velocity PID constants.

2. Switched to level 5 IMU filter
3. logging setpoints
4. Logging for up to 5 minutes
5. Also accounting for time spent during logging when calculating LOOP_TIME
6. Logging during manual mode now, too.

Fixed bug with logging. Was accidentally writing rows by 4 rather than by 1, and would write beyond the limits.
Also properly initializing the initial value of the hw_unix_timer so Valgrind doesn't complain.

This reverts commit 52bea9cd.

- uses virtual quad

Added safety checks for callback function pointer. Updated UART test scripts. Added graph_blocks to XSDK project.