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/fileio/gzstream/README

@@ -0,0 +1,6 @@
+
+                              gzstream
+      C++ iostream classes wrapping the zlib compression library.
+===========================================================================
+
+    See index.html for documentation and installation instructions.