Tab bar controller dynamically adds & removes child view controllers

Revert "Tab bar controller dynamically adds & removes child view controllers"

Tab bar controller dynamically adds & removes child view controllers

Tabs controller performs dynamic adding and removing of the tab view controller upon transitioning between view controllers.

Tab bar objective-c prefixes

Provided default values for when user set's nil as color for tab bar items.

Introducing tabBarItemsNormalColor and tabBarItemsSelectedColor