This commit also introduces a tempprary fix to an issue where fab is
displayed on wrong screen when switching between bottom tabs rapidly.

* Dispatch a navigation event whenever the side menu button is clicked (BottomTabsLayout)

* Dispatch a navigation event whenever the side menu button is clicked (SingleScreenLayout)

* Changed the way the navigatorEventId is retrieved in SingleScreenLayout.

The event is sent to the top most screen displayed in the current screenStack.

call setButtons with empty fab object to remove it

* Implement right SideMenu on Android

* Adapt toggleSideMenu and toggleSideMenuVisible to right SideMenu

* Move event emmiter logic out of Application

* Implement searchView

Usage:
```js
rightButtons: [
      {
        id: 'searchView',
        label: 'Search',
        hint: 'Search...'
      }
    ]
```

* Translucent TitleBar

* Collapse TopBar

* Less noticeable translucent effect

* Implement ScrollViewDetector

* Collapse on fling

* Collapse on touch up

Complete collapse on touch up instead of fling

This change means that in a tab based app, when pushing a screen
which did not declare `tabBarBackgroundColor` - the BottomTabs color
will persist from the previous screen and not be set to the default
color which is white. This eliminates the unwanted BottomTabs
background color change in this specific use case.

closes #409

When ivoking navigation actions such as push, pop etc, instead of
checking modal visibility, check if modal actually contains the given
navigator. This fix alows to change navigation state in screens while
modal is displayed.

* Don't show fab of a screen that's pushed to a none active tab
* Change fab when navigating back in the stack with back button
* Add screens before SnackbarAndFabContainer

fixes #274

* Created Snakbar class to encapsulate Snackbar logic.
* Clicking the action now emits event to current screen
* Action color works

This commit is the first step in adding proper screen transition
animations to push and pop actions.

works best with drawUnderTabBar

Since we don't fully support hideOnScroll property yet, draw all views
above BottomTabs