Initial leveldb stress test

Just logs messages to the database as they are received.
When receiving full rate ISOBUS, the process did *not* max out.
Added opcode support from ISOBlue to Android

Before only command from Android to ISOBlue used opcodes.
First attempt at being able to get past data
Fix bug in with processing consecutive commands

The function would return after finishing the first, leaving any others
in the buffer indefinitely.
Add past data testing to `isoblue_dummy`