Precompiled Header Proposal

Hello,

I went through the code base and moved all the common system includes into a precompiled header file.

Most of the important changes are in "utils.pch.h".  However, a lot of files had to be modified to do this correctly.  So, I apologize for the huge diff.

In addition, I updated the VS project files to use the precompiled header.  Someone will have to go out and modify the linux and OSX builds though.  However, they should still build in the mean time without explicitly changing anything.  This shouldn't break anything (Hopefully :P).

Anyways, let me know what you think or if you have any questions or comments.  There's probably a problem or two in there somewhere that needs addressed. :)

Thanks.