Replace ChanType.sepfds with Channel.bidir_fd This handles the case where a svrchansess has separate FDs for nopty, but a single FD for pty mode. The use of sepfds was also previously incorrect for X11 and agent forwarding

Tech Note #7
Quick building for testing with LTM

EXTRALIBS=-ltommath CFLAGS="-g3 -DLTC_NO_ASM -DUSE_LTM -DLTM_DESC" make -j3 IGNORE_SPEED=1 test