Transformer: Refactor to use graphie.addReflectButton
Transformer: Refactor to use graphie.addReflectButton

Test Plan:
 * move the reflection line's points
 * drag the reflection line
 * reflect a polygon over the reflection line
 * check for no js errors

Reviewers: alex

Reviewed By: alex

CC: alpert

Differential Revision: http://phabricator.khanacademy.org/D5596

chirilo/perseus,sachgits/perseus,daukantas/perseus,ariabuckles/perseus,learningequality/perseus,alexristich/perseus,ariabuckles/perseus,learningequality/perseus,junyiacademy/perseus,daukantas/perseus,alexristich/perseus,abe4mvp/perseus,iamchenxin/perseus,abe4mvp/perseus,chirilo/perseus,ariabuckles/perseus,huangins/perseus,sachgits/perseus,ariabuckles/perseus,iamchenxin/perseus,huangins/perseus,junyiacademy/perseus