Migration to Visual C++ 2010, availability of x64 builds

The 32-bit build is up at the buildbot download page. Direct link to the directory:
buildbot.panda3d.org/downloads/d … 86/builds/

The 64-bit build will be a while until I fix some issues with cross-compiling in makepanda (as our Windows buildbot is 32-bits).

I also removed the dependency on ATL, so now you don’t need to use --no-directcam any more in order to build the SDK with the free version of MSVC.