[PATCH][PHP_5_0] MSSQL Uniqueid formatting, etc...

Here's a patch to the MSSQL extention that:

1. Formats a resultant uniqueidentifer into a string (instead of raw binary)
   which is the same way that odbc handles them.

2. Enables uniqueids to be used from freetds if SYBUNIQUE is defined in the
   freetds code. I believe this is what the original author intended to do,
   since the current code doesn't do anything unless you add your own -D
   compile definition or change the code to work.

This patch could probably also be applied to the 4.3 and 5.1 trees without
modification, I haven't tried.

Jason