Fix game rendering on mobile devices

[averycrespi]

• Currently, the game doesn't render well on mobile devices
• We should properly use Bootstrap responsive grids to fix this
• Related: removal of sidebars (events)

[averycrespi]

• Depends on Remove event log #46
• Turn indicator: make more obvious? take up less space?
• Win/loss indicator: make more obvious (recolor all cells to match winner? modal?)