Fix v_args when used on classes with non-callable members

Add test data files to MANIFEST

Needed for tests to succeed on a packaged version of lark.

Include relative imports and rule rewrite

%import .local.foo -> bar

The `.` character is invalid as a group name in regex, replacing by `__`.
The bug arose in `lexer._build_mres`.

%import common.NUMBER -> N
%import .local.NUMBER -> N

# Conflicts:
#	README.md

Fix literal range escape assertion

Make VisitError inherit from LarkError

The recently added VisitError is the only lark exception not inheriting from LarkError,
which makes it painful to catch for client application.