Major code reorganization

This commit only updates the XCode project for the changes.
A later commit each will update it for scons and MSVC.

A few actual changes are mixed in:
- Add a prefix header for a handful of common definitions
- Moved current_cursor into the Cursor class as a static member
- Removed the make_cursor_sword and make_cursor_watch functions
- Include tests in the All target
- Remove redundant -l flags for Common and Common-Party (since they're included in the Link phases anyway)

src/scenedit/scen.actions.cpp

@@ -10,7 +10,7 @@
 #include "graphtool.hpp"
 #include "scen.graphics.hpp"
 #include "scen.actions.hpp"
-#include "soundtool.hpp"
+#include "sounds.hpp"
 #include "scen.core.hpp"
 #include "scen.fileio.hpp"
 #include "scen.keydlgs.hpp"