Disable -oldsync startup message.

A message is printed if you are playing a game using the old sync
code, which could put you at a disadvantage compared to other players.
Disable this message for now as we're defaulting to old sync for the
time being.
Allow -warp to episodes beyond episode 4.

Vanilla Doom's -warp parameter allows warping to episodes beyond E4.
This didn't work in Chocolate Doom because of some changes made
to the G_InitNew code before the source release. Actual decompilation
of that function in Vanilla Doom shows that the episode/map sanity
checking is not present:

http://pastie.org/8140437

There is at least one known WAD (2002ado) that has a map on E5M1
that is playable in Vanilla, and this stops that map from being
possible to play. Comment out that code because it obviously
doesn't deserve to be there.

This fixes #426. Thanks plumsinus.