preliminary code for presenting radios as ttys
switched ldisc receive_buf to use kfifo to process incomming packets; preparing to add buffers to radio ttys
added fifo for each radio tty
added initial termios in raw mode
standardised on unsigned char throughout code
added wait_event to ldisc_write to avoid returning zero
some naming changes (packet->transaction, message->transaction)
refactored startup code, fixed bug wherein tty_driver was not unregistered
used tty_port to retrieve tty associated with radio
update documentation