Improve static_cfref_cast so that it can be used without causing an unnecessary retain/release in the case when one is only using the cast to convert to a more-derived raw CF ref type.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@47403 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Don't include <CoreFoundation/CFBase.h> because it in turn includes MacTypes.h which causes too much namespace pollution.
Instead, declare the CFTypeRef type and the CFRelease and CFRetain functions.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@47401 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
