When attempting to navigate to a drawer item while the drawer's state
is 'opening' or 'closing' results in a state where the underlying navigator's
screen correctly changes but the drawer fails to automatically dismiss itself.
Instead, we should allow the drawer to respond to updates and change it's state
even if it's in the middle of 'opening' or 'closing'.
The index change event fires after swipe animation. If you quickly navigate to a new screen in stack before animation finishes, the index change event will fire after the previous navigation event. By this time, the tab navigator is not focused anymore. Using the JUMP_TO action instead of NAVIGATE avoids this issue.
Closes#16
When the statusbar is not translucent, the view resizes when the keyboard is shown on Android. The tab bar stays above the keyboard. This PR makes the tab bar hide automatically when the keyboard is shown.
The behaviour is enabled by default and can be disabled with `keyboardHidesTabBar: false` in `tabBarOptions`
### Motivation
Exposing `accessibilityRole` and `accessibilityStates` through props in the same way as `accessibilityLabel`. This allows screen readers to announce things like: `Selected. Banana. Button.`
Reasonable defaults were provided, however, consumers can provide custom overrides in the cases where the role might be `imagebutton` or the state might be `disabled`.
### Test plan
Select a button with VoiceOver (iOS) or Talkback (Android) enabled. The screen reader should read something like `Selected. <AccessibilityLabel>. Button.` or something slightly different depending on which platform you are on. Buttons that are not focused should not have `Selected` announced.
