Pymodbustcp

- fix multiple TCP packets recv issue in ModbusClient and ModbusServer (thanks Farin94).

- add long_list_to_word to utils.
- add float support as example.

- fix port and host accessors, change check now use "==" and not "is".

- setup now use setuptools.

- fix 'Rx' label on error.
- change file mode for server.py example.
- fix compatibility with modbus unit_id = 0 (thanks to mfkenney).
- fix compatibility for modbus frame with garbage.

- add toggle_bit() to utils.
- add server.py example.
- add HOWTO for safe PyPI upload.