Fix marshaling for wchar_t in C++ generator mode.
Fix marshaling for wchar_t in C++ generator mode.

ddobrev/CppSharp,mono/CppSharp,zillemarco/CppSharp,mono/CppSharp,mono/CppSharp,zillemarco/CppSharp,zillemarco/CppSharp,zillemarco/CppSharp,ddobrev/CppSharp,mono/CppSharp,mono/CppSharp,ddobrev/CppSharp,ddobrev/CppSharp,ddobrev/CppSharp,zillemarco/CppSharp,mono/CppSharp