Merge branch 'master' of https://git.ece.iastate.edu/danc/MicroCART_17-18

quad/executable.mk

quad/scripts/tests/test_safety_checks.rb

quad/scripts/tests/testing_library.rb

quad/src/graph_blocks/node_mixer.c

quad/src/quad_app/controllers.c

quad/src/quad_app/hw_iface.h

quad/src/quad_app/iic_utils.c

quad/src/quad_app/iic_utils.h

quad/src/quad_app/initialize_components.c

quad/src/quad_app/initialize_components.h

quad/src/quad_app/quad_app.c

quad/src/quad_app/sensor.c

quad/src/quad_app/sensor.h

quad/src/quad_app/type_def.h

quad/src/virt_quad/hw_impl_unix.c

quad/src/virt_quad/hw_impl_unix.h

quad/src/virt_quad/hw_impl_unix_i2c.c

quad/src/virt_quad/hw_impl_unix_imu.c

quad/src/virt_quad/hw_impl_unix_lidar.c

quad/src/virt_quad/hw_impl_unix_optical_flow.c