- add support of new device attribute which can specify the data type received
  by the plugin
- add missing brackets around bit shift for length in TLF to fix operator
  precedence
- add check in _read_entity() if data still contains enought bytes to read for
  the current field; otherwise throw exception
- update logging:
  . remove superfluous whitespace when logging data in debug mode
  . siltenly ignore entity read errors at EOF and correctly reset the stream
    to the next byte to try parse entites from there again
- add support for known device smart-meter-gateway-com-1
- add documentation about the device plugin attribute
- completely remove connection counter
# was just copyied but not used anywhere
- convert port argument to integer explicitely to make socket.connect() work
# connect() expected port parameter to be an integer
- try to do network connect with 2 seconds timeout and after that set socket
  to non-blocking mode
- remove logger in prepareHex()
Merge pull request #120 from ohinckel/issue-117-hex-devices

Sml Plugin: Support more devices using hex strings