Missed files from last commit

quad/computation_graph/src/node_accumulator.c

quad/computation_graph/src/node_accumulator.h

quad/computation_graph/src/node_add.c

quad/computation_graph/src/node_add.h

quad/computation_graph/src/node_constant.c

quad/computation_graph/src/node_constant.h

quad/computation_graph/src/node_gain.c

quad/computation_graph/src/node_gain.h

quad/computation_graph/src/node_mult.c

quad/computation_graph/src/node_mult.h

quad/computation_graph/src/node_pow.c

quad/computation_graph/src/node_pow.h

quad/sw/modular_quad_pid/src/main.c