Minor USDF Spec Revision

So awhile ago it came to my attention that the USDF spec is slightly out of line with the binary format. The description of the page block reads:

Starts a new page. Pages are automatically numbered starting at 0.

However, both USDC and ZDoom have implemented it as starting from 1. This makes sense as the vanilla binary format hacked the sign for if the dialog should close on choices. Since all known implementations are in line, should I go ahead and change the spec to match this?

Change the spec. Changing the implementation will certainly cause problems now, especially since the current spec differs from the binary format.

Since there are no objections the spec has been formally updated.

The copy of the specs in the ZDoom repository have not been updated.
http://www.doomworld.com/vb/doom-editing/62894-can-someone-help-me-with-u-zsdf/

All right, I have committed the updated document there as well. Amusing side note, I just saw that the new spec is 6,666 bytes.