* Add customIcon and customIconColor properties to ContextMenuAction
* Convert the new ContextMenuAction properties
* Set customIcon with customIconColor, if available, for the ContextMenu actions
* Add type declarations for new props
* Update README with new action props, fix other typos
* Add example for new action props
* Update readme and specify the higher priority of customIcon
* Refactor icon and iconColor props on iOS native side
* Remove "system" prefix from icon and iconColor on Android native side
* Update type declarations with new the new prop changes
* Update and format README
* Call processColor for iOS in index.js
* Switch android impl to use native contextmenu view
* Fix click callbacks
* Nested menus working on android
* Clean up
* Bump version
* Add icon functionality back to android context menus
Fix LongPress being accidentally fired for taps and scrolls.
The GestureDetector detects LongPress by processing ACTION_DOWN, setting a
timer to fire LongPress, then cancelling the timer upon receiving further
interaction events (eg ACTION_MOVE when scrolling is initiated, or ACTION_UP
when a finger is lifted, etc).
This changes ContextMenuView::onTouchEvent() to return true, as
false instructs the input system to stop forwarding successive events from the
current interaction, causing the GestureDetector to only see ACTION_DOWN events
and wrongly fire LongPress for every interaction.
