fixed extconf.rb for untyped data
wxSlider, wxSpinButton, wxSpinCtrl: fix attribute documentation
rb_define_attr_method: make it possible to define them read or write
only
main: define size function for classes that are not freed too
make it possible for classes that as Info to be freeable like wxImage
add nil_check overload that does take a klass VALUE as type name
wxWizard: document methods and attributes
wxProperty: make some attribute like methods, that rdoc thinks that they
are one
wxPalette: document some methods
wxStatusBar: document attributes
wxImage: add new methods and document more