Implemented get/set param, output, and source on the quadcopter.

quad/src/computation_graph/computation_graph.c

quad/src/computation_graph/computation_graph.h

quad/src/computation_graph/test/test_computation_graph.c

quad/src/quad_app/callbacks.c

quad/src/quad_app/util.c

quad/src/quad_app/util.h