Initial add of richtext modules.

git-svn-id: http://svn.wxwidgets.org/svn/wx/wxPython@74131 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Ignore some overloads which can't be disambiguated by the wrappers.
(Typically methods that only differ by constness in C++.)

git-svn-id: http://svn.wxwidgets.org/svn/wx/wxPython@74132 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Richtext needs wxXML declarations

git-svn-id: http://svn.wxwidgets.org/svn/wx/wxPython@74133 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
More tweaks for richtext buffer classes

git-svn-id: http://svn.wxwidgets.org/svn/wx/wxPython@74134 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775