Remove DLL export declaration from wxScrolled.

Remove DLL export declaration from wxScrolled.

As this class has only inline methods it doesn't need to be exported from the
DLL and actually exporting it results in linking problems when using
wxScrolled<wxWindow> (which, unlike wxScrolled<wxPanel>, is not used in wx
itself and so doesn't seem to be instantiated) in DLL client even with VC > 6.

An alternative solution would be to change WXDLLIMPEXP_TEMPLATE_INSTANCE_CORE
macro to explicitly instantiate the template in the DLL even for VC > 6 but
this wouldn't solve the problem for wxScrolled<CustomClass> while removing the
DLL export declaration should.

Also use wxScrolled<wxWindow> in addition to wxScrolled<wxPanel> in the scroll
sample to test that it links correctly.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62036 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775