wxProperty: add some extra check for Property#value_image= and fix
something in the _alloc function that did prevent to create an instance
of wxProperty
wxRichMessageDialog: fixed some macros
add wxCollapsiblePane
wxRect: add more attributes and document them
wxTextAttr: add _initialize_copy
add RichTextAttr
add RichTextStyle base style
add RichTextStyleSheet
added block functions to RichTextCtrl
add RichText classes to main rwx file