Upgrade underscore to 1.6.0
Upgrade underscore to 1.6.0

lotrfan/PrairieLearn,lotrfan/PrairieLearn,kevinwang/PrairieLearn,rbessick5/PrairieLearn,tbretl/PrairieLearn,kevinwang/PrairieLearn,rbessick5/PrairieLearn,parasgithub/PrairieLearn,PrairieLearn/PrairieLearnHack,lotrfan/PrairieLearn,PrairieLearn/PrairieLearnHack,lotrfan/PrairieLearn,PrairieLearn/PrairieLearnHack,PrairieLearn/PrairieLearnHack,tbretl/PrairieLearn,tbretl/PrairieLearn,lotrfan/PrairieLearn,kevinwang/PrairieLearn,PrairieLearn/PrairieLearnHack,mwest1066/PrairieLearn,lotrfan/PrairieLearn,jakebailey/PrairieLearn,tbretl/PrairieLearn,mwest1066/PrairieLearn,parasgithub/PrairieLearn,kevinwang/PrairieLearn,rbessick5/PrairieLearn,PrairieLearn/PrairieLearnHack,rbessick5/PrairieLearn,PrairieLearn/PrairieLearnHack,parasgithub/PrairieLearn,kevinwang/PrairieLearn,kevinwang/PrairieLearn,PrairieLearn/PrairieLearnHack,parasgithub/PrairieLearn,jakebailey/PrairieLearn,kevinwang/PrairieLearn,jakebailey/PrairieLearn,mwest1066/PrairieLearn,mwest1066/PrairieLearn,mwest1066/PrairieLearn,rbessick5/PrairieLearn,tbretl/PrairieLearn,lotrfan/PrairieLearn,parasgithub/PrairieLearn,jakebailey/PrairieLearn