
 * Improve error/warning messaging when parsing configuration file

 * Consider reworking line toggle and line pulse featueres in case requests are made to apply them to more lines:

     ctrl-t g Toggle serial line
     
     Which would then make tio ask which line to toggle:
     
     [20:50:11.691] Please enter which line number to toggle?
     [20:50:11.691] DTR(0) RTS(1) CTS(2) DSR(3) DCD(4) RI(5)
     
     ctrl-t p Pulse serial line
     
     [20:50:11.691] Please enter which line number to pulse?
     [20:50:11.691] DTR(0) RTS(1) CTS(2) DSR(3) DCD(4) RI(5)
     
     command-line:
     --line-pulse-duration="DTR=60,RTS=50,CTS=40,DSR=30,DCD=20,RI=10"
     
     config file:
     line-pulse-duration="DTR=60,RTS=50,CTS=40,DSR=30,DCD=20,RI=10"

 * Split I/O feature

   Allow to split input and output so that it is possible to manage these independently.

   The general idea is to redirect the output stream on the socket port number
   specified but then redirect the input stream on the same port number + 1.

   Example:

   tio /dev/ttyUSB0 --socket inet:4444,split-io

   Will result in output stream being hosted on port 4444 and input stream hosted on port 4445.

   For file sockets something similar can be arranged:

   tio /dev/ttyUSB0 --socket unix:/tmp/tio-socket-0,split-io

   Will result in output stream being hosted via /tmp/tio-socket-0 and input stream hosted via /tmp/tio-socket-0_input
