TMXR: Added loopback support for datagram configured lines to pass full packets in loopback mode.
H316: Added support for proper max data packet size transmission and reception in h316_udp.c
H316: Fix compiler warning
MAKEFILE: Give more clear information when issuing missing libSDL library to enable video capabilities #90
H316: Added "SET dev LOCALLOOP" and "SET dev NOLOCALLOOP" commands to the IMP modem device so that loopback mode can be changed by commands instead of just programatically.