Adding lark-cython support

[geographika]

Currently 12 failing tests relating to comment parsing. Possibly related to 1.0.0 change:

v_args(meta=True) now gives meta as the first argument. i.e. (meta, children).

However tests run fine without lark-cython.

Failing code:

    def _assign_comments(self, _tree, prev_end_line):

        for node in _tree.children:
            if not isinstance(node, Tree):
                continue

            try:
>               line = node.meta.line
E               AttributeError: 'Meta' object has no attribute 'line'