We now get the property when we go past the currently-fetched depth but we do not...

We now get the property when we go past the currently-fetched depth but we do not have the display updating yet

* Source/DebuggerConnection.h: New ivar _depthFetchElement to record the element that requested more registers
* Source/DebuggerConnection.m:
([DebuggerConnection dataReceived:deliverTo:]): Removed an NSLog()
([DebuggerConnection getProperty:forElement:]): New method that gets a specified property for a specific element
([DebuggerConnection propertyReceived:]): Recived data delivery handler for getProperty:forElement:
* Source/DebuggerWindowController.m:
([DebuggerWindowController outlineViewItemDidExpand:]): Call the getProperty:forElement: method to get deeper properties
* English.lproj/Debugger.nib: Set the delegate of the NSOutlineView to be the first responder