Quad i2c rework

See merge request !12

- use shared memory instead of fifos for most I/O
- re-enable functional tests

Updated model to include velocity controller and two degrees freedom controllers, still contains bug

Had to make small changes to headers in quad inc

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