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/pcedit/pc.graphics.hpp

@@ -3,4 +3,3 @@ void init_main_buttons();
 void Set_up_win ();
 void redraw_screen();
 void do_button_action(short which_pc,short which_button);
-void make_cursor_sword();