Added a .gitattributes file to help with png diffs and with git archive calls.

Thanks to stefanbeller who reminded me to do that when making one for
Polymorphable. :)
Made the time before reinforcements with dark soldiers be 3:00 instead of 2:00.

Requested by Shirish after some play-testing.:)
Fixed a nasty bug in the wolf cave script.

Kudos to Shirish for pointing that one.