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.

call setButtons with empty fab object to remove it

https://github.com/wix/react-native-navigation/issues/297

* 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

fixes #226

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.

TopTabParams are a subset of ScreenParams, moved the properties that
are shared by both classes to BaseScreenParams.
This change was needed to report screen changes properly in ViewPagerScreen

fixes #274

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