Player: RS232 Add HEX support

implemented

#1

Add support for sending HEX commands to the RS232 command functionality.

We would need another control character in the command string to indicate whether or not the string should be considered HEX.

Example code snippit:

string str = "7E 00 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 00 FF";
byte[] bytes = str.Split(' ').Select(s => Convert.ToByte(s, 16)).ToArray();
serialport.Write(bytes, 0, bytes.Length);

closed #2