* collection of various fixes and edits

* collection of various fixes and edits
    - removed <10.3 support in the preferences' code
    - added preliminary support for Obj-C 2.0 / Garbage Collection
        - needs to be enabled manually in intf.h for now and is restricted to future Darwin release
    - updated various copyright dates to approbate values
    - configured the source tree in the Xcode project for future Xcode releases
    - finally renamed the Xcode project to the correct bundle extension