Support for ELM327 modules

[richClubb]

Adding support for ELM327 modules

[richClubb]

Investigation into ELM327 support found the following

• It has its own ISO TP
• Only supports a limited number of baudrates on CAN, not sure what the full extent is. 500 and 250 is common
• Easy to transmit but hard to receive data

Command set and documentation available: https://www.elmelectronics.com/wp-content/uploads/2016/07/ELM327DS.pdf

AT MA command dumps the bus data AD BD dumps the last CAN bus command

sending arbitrary can messages: https://www.elmelectronics.com/wp-content/uploads/2017/11/AppNote07.pdf

[richClubb]

This is shelved for the time being, it would require strange integration into the current architecture but is not out of the question for the future