Summary: This adds a new event `onSearchBarCancelPressed` that fires
when the user presses the cancel button on the search bar in the
navigation bar. `onSearchBarUpdated` does indirectly fire when the user
presses cancel, as the query will be reset to an empty string, but it is
not possible to distinguish those events from the user simply resetting
the query. My use case for this is to have a view that appears on top of
the normal content of the view controller when the search bar is
focused.

Test Plan: ran `npm run test-js` and confirmed added JS unit tests
passed.

I also tested this with my app, and confirmed the
`onSearchBarCancelPressed` method was called when I pressed the cancel
button.

* Refactored backButton api

* Move StackController to separate package

Implement BackButtonOptions

* Somewhat simplify StackController creation in tests

* Pull backButton logic from StackController

* Handle all TopBar button options in TopBarButtons

* fix back button on iOS

* add addicional options to tabbar

* fix tests

* [ios11+] Add searchBar option for topBar

* Fix formatting and linter issues

* Add docs about topBar.searchBar

* Fix missing semicolons

* Revert prettier changes

* Add js tests for onSearchBarUpdated to achieve 100% coverage

* Mark searchBar test as :ios: specific

* pass props for topBar background component

* refactored custom components

* pass props for topBar background component

* refactored custom components

* refactored RNNOptions object

* Use margin to control component position relative to TopBar

RelativeLayout rules caused excessive CPU usage due to issues with RN's
keyboard detection mechanism (based on global layout listener)

* Skip custom transition e2e on Android

* Improved the clarity of the top-level API doc (#2984)

I clarified some of the language here so that it is easier for the beginner to understand. (It was a little bit awkward before)

* Increase gradle daemon process memory

* Disable Orientation test on Android

* Fix SideMenu e2e

* Fix popTo

* Use margin instead of RelativeLayout rules to align component to BottomTabs

Rules caused excessive CPU usage due to RN issue with global layout listener
and keyboard visibility detection.

* Update README.md

for triggering build

* Update README.md

* Consolidate pop and animatePop

* Update top-level-api.md ... more copyediting. (#3002)

Further clarification of some of the top level API stuff.

* popTo animates top screen

* Refactor component options on Android

* Stop processing passProps from options

* removed comments

* Refactor TopBar options, introduce title options

* Update background to new api

* Refactored topBar options on iOS

* Initial react component in TitleBar android

* set height to react view in TitleBar

* fix tests and lint

* ios unit tests fix

* custom titleView support

* custom navBar and titleView support

Closes #653

* refactored navigation options

* test fix

* better namings

* screen Background Color iOS

* ios v2 topBarTextFontFamily

* added topBarHidden to iOS

* minor fix and topBarHideOnScroll

* minor fix

* topBarButtonColor iOS

* topBarTranslucent iOS

* topBarTranslucent IOS minor fixes

* eslint fixes

* minor fixes

* changed setTabBadge to tabBadge and added a unit test in iOS

* added fontSize on iOS

* minor fix

* topBarTransparent

* minor fix

* first dirty custom transition iOS poc. in need of complete refactor and testing

* dirty poc for view transition

* dirty poc of interactive transition

* deleted unNeeded Files

* cleaning

* cleaning, support for interactiveImagePop and backButton custom transition

* cleaning

* merge v2 into custom-transition-animation fix

* merge fix

* merge fix

* cleaning and merge fix

* support for multiple animation in parralel, animations with are not shared element including: velocity, spring, alpha and translate

* last commit should also include these

* added resize mode animation and fixed flickering bug

* refactoring

* first cleaning and another test

* cleaning

* commandsHandler now accepts bridge in constructor, fixed tests, added e2e test

* eslint

* android pop now recieves two parameters - preparation for custom transition

* Refactor + add afterLoad to modal

* merge v2 second try

* merge fix

* merge fix

* fix ios unit tests

* fixed topBarTransparent e2e

* fix js tests

* refactored RNNAnimator, RNNAnimatedView, small fixes

* refactor topBarLargeTitle

* fixed lifycycle bug with componentWillUnmount, small fixes

* fix transparent conflict

* removered Element.js from coverage report

* comment redundent test
(still needs to be discussed), small fix

* removed commented test, moved element.js to adapters

* readme

* WIP

* ios, tests

* refactoring

* test fix

* probabl test fix