Fix Transformer ToolsBar toggling
Fix Transformer ToolsBar toggling

Summary:
The different transformation tool buttons stopped toggling when pressed,
preventing you from unsummoning a tool after it was summoned, except by
summoning a different tool. This change fixes the ability to unsummon a
tool by clicking that tool's button again (which should be in a
depressed state before this second click).

Test Plan:
visit test.html
add a rotation tool
click the rotation button again
verify that there are no transformation tools on the graph anymore

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