Initial release

Initial version of VField, a vector field visualization library. This version can draw field lines or vector fields. Sources are either charge configurations, or an arbitrary vector valued function. It is focused on authoring instructional content, and will continue to evolve as needs are encountered in authoring content. Additional features can be added on request, add a github issue if you find problems or need additional features.

A version 2 is in the works which will use custom tags rather than a configuration object.