wrobstory/vincent — pull request #99 by Midnighter (2014-02-16 19:39:39+00:00)
Title: add more marks, transforms and properties

This adds checks and more of the documented transforms and marks and their properties.

I'm a little confused as to which properties of marks and transforms are implemented directly and which ones are deferred to the `PropertySet`. Let me know if I should change anything around.