Add ShapePath::current_position()

[baozaolaoba-top]

In v0.11.0, current_position is a useful method, especially in the scenario of custom drawing svg. Can this function be added back in the latest version?

[Nilirad]

ShapePath is now implemented differently. It no longer has a builder, but is just a Vec<Action> which is evaluated lazily in the Geometry::add_geometry method.

Theoretically, it is possible to add a current_position field to ShapePath and update its value in each method, but it is not trivial to do for methods who do not have an explicit end position, like arc. The implementation is not trivial in lyon, so if someone is willing to do it, can open a PR addressing this issue.