This commit introduces an option to control the way components are pushed into the stack.
When pushing components into a stack, they are pushed the moment they are measured.
If `waitForRender` is true, components will be pushed only after the initial render.

api:

```js
options: {
  animations: {
    push: {
      waitForRender: true
    },
    showModal: {
      waitForRender: true
    }
  }
}
```

This commit removes NavigationOptionsListener as it was not needed anymore.
As a result, it uncovered a few issues which this commit also aims to fix.

* Set SideMenuController as parent of left, right and centre controllers
* Select tab by id with tabSelector interface
* mergeOptions now also applies options after merge - in ViewController base class
* Pull presentation logic from ComponentLayout to ComponentViewController

* Change topBar backgroundColor to Color object

* StackLayout implementation

Unfortunately, this commit also contains a lot of refactoring and a few
bug fixes relating to styles.

* TopBar is not part of Component, instead it's a part of StackLayout
  and shared between all components pushed to the stack Similar to iOS.
* Handle ScrollEvent in ReactView instead of passing the listener down
* Implement Fraction and Text null objects for style params
* Converted a few style params to null objects. This fixes some styles
  being applied even when they were not specified explicitly.
* Stop sending null promise to commands
* Seperate push and pop into animatePush/push and animatePop/pop
  to avoid boolean param

* Adapt TopTabs to new API

* Deleted getContentView method
* Delete Custom dialog code
* Delete topTab code
* sendOnNavigationButtonPressed was pulled to a dedicated interface

* upstream merge

* Fixed bad merge

* More bad merges

* Mostly done, however a few properties missing and tests remain.

* async icons loading

* Left button

* Whoops!

* Added button size

* updated docs

* refactor

* Rebase fixes

* Rebase fixes

* rebase fix

* Rebase fixes

* rebase fixes

* reset contributing

* Further work on TopTabs and some refactoring

* OptionsPresenter receives views as params
* Remove TopBar and style logic from ViewControllers, these are the OptionsPresenters concern
* StackAnimator isn't coupled to LinearLayout
* Convert Runnable to lambda
* ContainerLayout now implements ReactContainer interface
* Enable desugaring in playground app

* TopTabs unit tests

* Restructure TopTabsLayout

* Refactor Containers

* Consolidate view creators. For some reason we had double abstraction layer and had creators invoking creators
* Rename ContainerView to ContainerLayout

* fix test