code style fixes:

- reordered includes to prevent accidental dependencies.
- moved arch specific files into their own folder (easier to include with cmake).
- renamed non-class files to reflect new code style (lower case with underscores).
- using full relative paths for includes (easier for understanding dependencies).
- using #pragma once instead of classic-style header guards.

src/lib/platform/MSWindowsUtil.cpp

@@ -16,8 +16,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "CMSWindowsUtil.h"
-#include "CStringUtil.h"
+#include "platform/MSWindowsUtil.h"
+
+#include "base/StringUtil.h"
+
 #include <stdio.h>
 
 //