Previously wxDECLARE_CLASS was a synonym for wxDECLARE_DYNAMIC_CLASS which was
inconsistent with its documentation and wxIMPLEMENT_CLASS that was the same as
wxIMPLEMENT_ABSTRACT_CLASS.
Resolve this in the most backwards compatible and also arguably logical way.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67879 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
