Implement better handling of situations when read() captures multiple
TNC frames; ensure each frame is handled in src/server.c, function
handle_iface(), to ensure packets aren't ignored before the next
select() call
Use KISS framing for raw sockets to avoid multiple write() calls from
being buffered, which caused read() on the other end of a file
descriptor to read more than frame at once
Significantly simplify dictionaries so that dictionary keys are always
uint32_t; this number can be an arbitrary integer, be it a file
descriptor, for instance, or a hashed value
Move raw frame interface capture to patty_ax25_if, patty_ax25_sock; this
resolves the issue wherein only bytes received, not sent, would be
captured by a raw socket bound to a specific interface with setsockopt()
