libspeedwire

introduced classes for speedwire credentials

reworked SpeedwireCommand and SpeedwireData to handle different types of commands, devices, access modes, etc.

added SpeedwireRawDataYield and SpeedwireRawDataEvent classes to deal with energy yield and device event records

added support for speedwire packets containing timeline and event data

reworked handling of well-known status and register tags; do not interpret conn == 0x00 register values