Allow wxAny to contain 'const char*' or 'const wchar_t*'. This was previously not...

Allow wxAny to contain 'const char*' or 'const wchar_t*'. This was previously not possible since these pointers were converted to wxString, as convenient means to work with string literals. Now pointers (to string literals) are stored instead, and As<wxString>(), comparison operators do the type conversion.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64106 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775