keep large answers from appearing (TNL-441)

@cptvitamin @talbs 

Before:
![screen shot 2014-09-19 at 9 54 56 am](https://cloud.githubusercontent.com/assets/2748698/4336230/9ee89306-4004-11e4-99c1-8dec51c7359a.png)

After:
![screen shot 2014-09-19 at 9 55 17 am](https://cloud.githubusercontent.com/assets/2748698/4336231/a63ec468-4004-11e4-811f-102f83e89daf.png)

Test in the text input problem on this page: 
https://edge.edx.org/courses/alp/9999/adamtest/courseware/6ae0c6cb9c7747c4b0ac610e8510aa81/2d791aeac09c4e30a2db99beab9e9af5/2