Fix chain launching

Basically you're not allowed to launch off a chain the frame you touch it anymore.

Coincidentally the changes here allow you to actually use PF_*STASIS in a Lua script now and have it work as you'd expect it to (it lasts for a tic).

src/p_inter.c

@@ -1339,6 +1339,9 @@ void P_TouchSpecialThing(mobj_t *special, mobj_t *toucher, boolean heightcheck)
}
else
player->pflags |= PF_ITEMHANG;
+
+			// Can't jump first frame
+			player->pflags |= PF_JUMPSTASIS;
return;
case MT_BIGMINE:
case MT_BIGAIRMINE: