Add more serial parameters: datasize, parity ad stop bit.
In openhab.cfg, config line can look like:
modbus:serial.slave1.connection=/dev/ttyUSB0:19200:8:even:1

Signed-off-by: Lionel Beard <beard.lionel@gmail.com>
Merge pull request #1592 from xiboy/master

[Modbus Binding] Add more serial configurable parameters: datasize, parity and stop bit.