Summary:
Fixes: T1334
remove final InboxApp references
move out all underscore-plus methods
Mass find and replace of underscore-plus
sed -i '' -- 's/underscore-plus/underscore/g' **/*.coffee
sed -i '' -- 's/underscore-plus/underscore/g' **/*.cjsx
Test Plan: edgehill --test
Reviewers: bengotow
Reviewed By: bengotow
Differential Revision: https://phab.nylas.com/D1534