macosx: get rid of the infamous 'get' prefixes everywhere and finally respect Cocoa's naming scheme here

macosx: updated used Cocoa methods to the current definitions and fixed a few logic errors, which only occur in 64 bit mode

 It removes the need of INPUT_GET_BYTE_POSITION/INPUT_SET_BYTE_SIZE which where
not thread safe.

macosx: In bookmarks's dealloc, we shouldn't release the p_old_input ptr, as we have already released it.

This should fix a crash reported in our bugreport ml.

Enforce access to input_item_t through input_item_{G,S}et*()
Unlock mutexes before calling these functions
Free strings returned by input_item_Get*()

New functions added:

char * input_item_GetURI( input_item_t  * )
void input_item_SetURI( input_item_t * , char * )

mtime_t input_item_GetDuration( input_item_t * )
void input_item_SetDuration( input_item_t * , mtime_t )

to access input_item_t->psz_uri and input_item_t->i_duration

    - 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

* the remaining compilation fixes plus a bit of clean up here and there. vout.m needs further fixing and everything needs quite some testing

* Fix some cosmetics

    - complete functionality except "Extract" (I'm going to fix that next week)
* MainMenu.nib: re-orded the window-menu a bit
* wizard.*: added a method to launch it from the bookmarks