C++: Add Page 4 - Container to dwtestoo. Had to rename ListBoxes G/SetText() to G/SetListText(). Since TextEntry has the same names but with different signatures. Thought it should be able to differentiate, but it errored as ambiguous. Also make ListSelect unsigned int since it should never be negative.

[Desktop Entry]
Name=Dynamic Windows Test
Exec=@prefix@/bin/dwtest 
Terminal=false
MultipleArgs=false
Type=Application
Categories=Application;Development;X-Red-Hat-Base;