Add defs values for AX-S1. Change classes to look up register values by device name
Fix bug where CCW angle limit methods were actually changing CW angle limit
Start adding AXS1 support
Add AX-S1 specific example script
Only list the start of a two-byte register in defs
PEP8 Cleanup, re-org some methods
Move register_length() static method into the dynamixel and sensor classes as these are module specific props; PEP8 cleanup