Remove MSVC6 support.

Don't support this compiler any more, this allows to get rid of tons of
MSVC6-specific workarounds, in particular we can now use Bind() and natural
template functions calls in the library code.

Also remove MSVC6 project and solution files and don't generate them when
bakefile_gen is ran any more (removing the remaining occurrences of msvc6prj
from the bakefiles results in weird bake-time errors, so it's simpler to just
leave them there).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76532 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/meta/if.h

@@ -12,27 +12,11 @@
 
 #include "wx/defs.h"
 
-// NB: This code is intentionally written without partial templates
-//     specialization, because some older compilers (notably VC6) don't
-//     support it.
-
 namespace wxPrivate
 {
 
 template <bool Cond>
-struct wxIfImpl
-
-// broken VC6 needs not just an incomplete template class declaration but a
-// "skeleton" declaration of the specialized versions below as it apparently
-// tries to look up the types in the generic template definition at some moment
-// even though it ends up by using the correct specialization in the end -- but
-// without this skeleton it doesn't recognize Result as a class at all below
-#if defined(__VISUALC__) && !wxCHECK_VISUALC_VERSION(7)
-{
-    template<typename TTrue, typename TFalse> struct Result {};
-}
-#endif // VC++ <= 6
-;
+struct wxIfImpl;
 
 // specialization for true:
 template <>