Allow parameters when registering tools and editors

[alexandrep-explorai]

Currently the RubberbandPath tool and the PathEditor that are implemented in annotorious/plugin-tools have some functionalities that I feel could be made optional instead of always being the default. I for one would love to be able to use these without allowing the user to toggle corners into curves, or to close the paths that they draw.

It could be great if one could supply configurations when registering a tool or an editor to control some of the aspects of its behavior.