Khan/khan-exercises — pull request #11145 by eltacodeldiablo (2012-01-13 17:17:02+00:00)
Title: Fixes problems lines/squares to show up and misc

This allows the problems 'lines' and 'squares' to show up without error.
I also added data-forms to percent to help with input errors.

[Trello](https://trello.com/card/board/recognizing-percents/4d87e664967a0775082939ab/4e793cc9c9d0fde99221dc9f)