Added NSAlert, NSButton Control, NSSharingServicePicker, NSPopover and more

146: 2013-08-24 by VVB
    - Added NSAlert, NSButton NSControl, NSSharingService/Picker, NSPopover, NSViewController, NSWindowController, NSPanel, filled out NSView, NSControl, NSApplication.
    - Added constructor from Ptr and WithFrame to NSControl, and added convienience methods to get the NSObject and NSView.
    - Added convienience extensions for window to return NSWindow, for control to return NSControl and return NSView.
    - Added ShareTemplate to SystemIcons and NSImage.
    - Added missing images to system images example.