Initial work on changing control_algorithm to use graph. Probably doesn't compile yet.

quad/sw/modular_quad_pid/src/computation_graph.c

quad/sw/modular_quad_pid/src/computation_graph.h

quad/sw/modular_quad_pid/src/control_algorithm.c

quad/sw/modular_quad_pid/src/graph_blocks/node_bounds.c

quad/sw/modular_quad_pid/src/graph_blocks/node_bounds.h

quad/sw/modular_quad_pid/src/graph_blocks/node_constant.c

quad/sw/modular_quad_pid/src/graph_blocks/node_constant.h

quad/sw/modular_quad_pid/src/graph_blocks/node_pid.c

quad/sw/modular_quad_pid/src/graph_blocks/node_pid.h

quad/sw/modular_quad_pid/src/main.c

quad/sw/modular_quad_pid/src/type_def.h