Added NzInputStream

Added NzFile::Read(buffer, size)
NzFile::Read(nullptr, size) now acts as a skip function (ex: SetCursorPos(GetCursorPos() + size)

include/Nazara/Core/Error.hpp

@@ -8,6 +8,7 @@
 #define NAZARA_ERROR_HPP
 
 #include <Nazara/Prerequesites.hpp>
+#include <Nazara/Core/Config.hpp>
 #include <Nazara/Core/String.hpp>
 
 #if NAZARA_CORE_ENABLE_ASSERTS || defined(NAZARA_DEBUG)