Added boxes to completing the square exercises
Cleaned up answer area
Cleaned up answer area
Merge branch 'completeSquare' of https://github.com/Helpsypoo/khan-exercises into completeSquare
Merge branch 'completeSquare' of github.com:Helpsypoo/khan-exercises into complete-square

Conflicts:
	exercises/completing_the_square_1.html
	exercises/completing_the_square_2.html
Include the full answer in the last hint

Test plan: Hit: http://localhost:8000/exercises/completing_the_square_1.html?debug and http://localhost:8000/exercises/completing_the_square_2.html?debug for each problem type, take all the hints, answer the question.

Auditors: emily
Merge branch 'complete-square'