Betrayer: Fix reflections on lake

Finally figured it out! The trick was that I had to use r2.z as the depth
instead of r2.w as I had first assumed. I'm guessing this was to do with
needing the depth of the object being reflected as opposed to the depth of the
water, but I'm not sure.

Whatever the case, the reflections are now 100% perfect and this lake looks
absolutely stunning in 3D =D
mkrelease: Add date to zip file

Because I hate unversioned releases. While this isn't a formal version number
it's straight forward and should suffice (so long as I only do one release of a
given game a day).
Fix .gitignore location

Bah, I was in the wrong directory when I added this!