Month view should adjust to display badges with event count instead of event list on mobile and tablets.

Summary: Ref T4392, Month view should adjust to display badges with event count instead of event list on mobile and tablets.

Test Plan: Open month view, adjust browser as mobile size, event lists should turn into badges with event counts and calendar days should be links to day views of those days.

Reviewers: epriestley, #blessed_reviewers, chad

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin, epriestley

Maniphest Tasks: T4392

Differential Revision: https://secure.phabricator.com/D12820