edx/edx-platform — pull request #1914 by polesye (2013-12-11 11:39:12+00:00)
Title: Show answer for imageresponse

[BLD-21](https://edx-wiki.atlassian.net/browse/BLD-21)

"Show answer" on imageresponse should highlight the area that would have earned full credit if the student had left her marker there.

Example of XML:
```xml

Explanation

The animal on the right is a kitten. The animal on the left is a puppy, not a kitten.

```
@jmclaus and @auraz please review.