Switch image_desync to use CameraInfo

same information with less bandwidth
image_desync now explicitly notices camera failures

nan for both, -inf for left, inf for right
Run image_desync node for both stereo pairs
Respawn all camera nodes if they die
Make image_desync much smarter

Now it restarts failing cameras and produces a flow which summarizes
camera state
Increase buffer depth on status_word publisher

Since each servo publishes its own message, they can stack up.
Improve pause switch

Smarter about failing enables
publishes summary state for executive
Remove enable/disable from teleop node

These are handled by pause_switch now.
fix gitignore

was ignoring CMakelists in subdirectories, I mean only exactly the one in src.
Reverse sense of pause switch

so system boots up in pause mode.
More logging in motion_node
Only accept home goal if no command source

So nothing can switch the machine out of homing mode
WIP, master executive
Beginning of executive
Merge branch 'executive'