online-exhibitions-viewer padding & breadcrumb fix

[AshGDS]

http://test.nationalarchives.gov.uk/agincourt/campaign-and-battle/account-of-agincourt-page-3/

[domjngo]

• Remove border-top from breather and add to h1
• Left align bottom button

[sdwilkes]

@AshTNA Could we add some padding to the H3 toggle class? This should increase the hit area for mobile users. Also, the arrow looks a bit squished