Fix tray scrolling (#392)
* Calculate Tray max-height in JS
* Use padding instead of margin for top and bottom of menu
* Add scrollDirection prop to CollectionView to prevent unwanted horizontal scrollbars on Windows
* Fix tray exit animation on Edge
* Prevent scrollbar shifting page when setting overflow: hidden on body
* Add shouldCloseOnBlur prop to Tray
* Fix press state being retained on Picker in Safari when closed with Escape
* Fix tests
