normalized different register names for devices with and without
multiple UART
implemented initialization of multiple UART
implemented initialization of asynchronous mode for multiple UART
implemented UART for devices with multiple UART
added documentation of serial phone cable
"private" functions start with _
intrpoduced new state for empty queue
made fbus data a pointer with dynamically allocated length
implemented asynchronous timer function for sending frame to phone.
introduced macros for checking fbus states ready/error.
introduced macros for checking fbus states ready/error.
implemented blocking write to fifo
implemented sending of fbus frame