Add more shapes to Transformer Widget

Summary:
Add polygons of various sidecounts, as well as lines, to the transformer
widget

Test Plan:
visit test.html and change the type to "2 lines"
perform some manipulations and make sure everything works (visually and
scoring)

Reviewers: alex

Reviewed By: alex

Differential Revision: http://phabricator.khanacademy.org/D5018