Khan/khan-exercises — pull request #24861 by xymostech (2012-06-26 00:03:38+00:00)
Title: Major improvements to the congruency framework

Make the functions and properties of angles and lines more consistent. Add a way to store and retrieve states in the custom answer type easily, as well as a way to restore the selections. Create named points and allow angles and lines to be referenced by their names.

@mwittels @beneater review?