Clarify language in readme for bitmap screenshots.
Clarify language in readme for bitmap screenshots.

timoschloesser/turbolinks-android,gavinliu/turbolinks-android,gavinliu/turbolinks-android,turbolinks/turbolinks-android,turbolinks/turbolinks-android,timoschloesser/turbolinks-android,timoschloesser/turbolinks-android,gavinliu/turbolinks-android,timoschloesser/turbolinks-android,turbolinks/turbolinks-android,turbolinks/turbolinks-android,gavinliu/turbolinks-android