Also drop some unused files. Renamed: - `core/dvector.h` -> `pool_vector.h` - `core/io/resource_import.h` -> `resource_importer.h` - `core/sort.h` -> `sort_array.h` - `core/string_db.h` -> `string_name.h` Dropped: - `core/allocators.h` - `core/os/shell.h` - `core/variant_construct_string.cpp`