- Added new_copy to all types, since trivial copy won't work for all
types.
- Added functions to convert from String to char array types, which is
not provided by the methods bound in Variant.
- Added operator index to String.
- Added missing cstring version of some Variant functions. They existed
in the header but didn't have the implementation and were missing from
the gdnative_api.json file.
- Added support for static calls on Variant types.