Improve support for iPhone X

[fcanas]

This pull requests fixes two issues affecting iPhone X

• The video controls should respect the bottom margin
• The home indicator view should appear and disappear with the decorator views

[fcanas]

I closed this because I never heard back from the maintainers. If these and other changes I've made are wanted, let me know and I can re-open a PR.

[netspencer]

interesting to see no response. i'd love to see this merged