Make P4Ruby build using VC++ 2005 or later using a -sTYPE=dyn API
This requires that we remove libcmt.lib from the link, and use /MD
instead of /MT on the compile phase. I also had to add a nasty
hack to run the manifest tool - nasty because it assumes it's
there and that it's necessary. Building with VC++ 2003 will now
probably appear to fail.