Eliminate vtkUnicodeString and array type

Charts/Core/Testing/Cxx/TestContextUnicode.cxx

Charts/Core/Testing/Cxx/TestFreeTypeRender.cxx

Charts/Core/Testing/Cxx/TestQtContextUnicode.cxx

Common/Core/CMakeLists.txt

Common/Core/CaseFolding.txt

Common/Core/Testing/Cxx/CMakeLists.txt

Common/Core/Testing/Cxx/TestArrayCasting.cxx

Common/Core/Testing/Cxx/TestUnicodeStringAPI.cxx

Common/Core/Testing/Cxx/TestUnicodeStringArrayAPI.cxx

Common/Core/Testing/Python/CMakeLists.txt

Common/Core/Testing/Python/TestStdVector.py

Common/Core/Testing/Python/TestStrings.py

Common/Core/Testing/Python/TestVariant.py

Common/Core/vtkAbstractArray.cxx

Common/Core/vtkArray.cxx

Common/Core/vtkArrayIteratorTemplate.h

Common/Core/vtkArrayIteratorTemplateInstantiate.cxx

Common/Core/vtkSetGet.h

Common/Core/vtkType.h

Common/Core/vtkUnicodeString.cmake