Revert translate() back to Raphael default

Summary: Undo override of Raphael translate() function. Fixes problems with representing_numbers.html and divisibility_intuition.html.

Test Plan: Tested the above exercises and visualizing_derivatives.html locally.

Reviewers: eater, alpert

Reviewed By: alpert

CC: tom, alpert, michaelchang

Differential Revision: http://phabricator.khanacademy.org/D1026