At least the BE and the NL DSMR devices use MBUS.
Therefor we make the MBUS obis reference generic, and convert the V5
telegram to use MBUS values.
Also remove BELGIUM_MAX_POWER_PER_PHASE as this was a duplicate.
Finally set self.maxDiff = None to have a full test output on some
tests.
* issue-51-telegram improved mbus device parsing; refactored TelegramParser.parse to return Telegram object which is backwards compatible with the dict result