This should help avoid issues from integer overflow (which is technically undefined behaviour)
while also allowing such issues to be addressed centrally if they still exist.
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)
