Compiler upgrade

Hi All,

I've finally taken the leap and upgraded my C++ compiler. Assuming nothing goes too far awry this time (unlike last time), the next release of L3DT will be built with MSVC9, along with any plugins that are upgraded between now and then. As far as I can tell, this change won't require all plugins to be recompiled, but I'll do some more tests just to be sure.

Cheerio, Aaron.