Minor across-board bugfixes re the past 24 hours of commits.

* d_main.c - fix the wipedef for skipping to the titlescreen to be the checkered one again.
* k_kart.c - Tweak drawtime's setting slightly.
* y_inter.c - Make endtic ALWAYS set when not netgame/splitscreen, to prevent an undesirable, possible hang whenever we add more stuff later.