[regress/cipher-speed.sh regress/forcecommand.sh regress/forwarding.sh] Sync regress tests to -current; include dtucker@'s new cfgmatch and forcecommand tests. Add cipher-speed.sh test (not linked in yet)
[regress/forwarding.sh] Regress test for ClearAllForwardings (bz #994); ok markus@
Add ${EXEEXT}: required to work on Cygwin.