Hotfix on Build 572

I just pushed another patch to build 572.  The build number is still 572.  Here is what was changed:

- fixed a bug with the new tcp rcon feature which caused windows servers to crash as soon as you start them

- fixed a bug where using /msg without any players in the server would crash the server badly

- improved autoupdate; autoupdate now reuses one connection for all files instead opening a new http connection for every file.  This creates up to an (estimated) 75% performance increase for small files, especially for users who are outside the USA or otherwise far away from the update servers latency-wise.