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/cmd/synergyc/OSXClientTaskBarReceiver.cpp

@@ -16,8 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "COSXClientTaskBarReceiver.h"
-#include "CArch.h"
+#include "synergyc/OSXClientTaskBarReceiver.h"
+#include "arch/Arch.h"
 
 //
 // COSXClientTaskBarReceiver