Adds TransitionManager.
Adds some useful transitions.
ChangeMockupView action receives a Transition.
Controller manages a list of Disposables.
Adds meaningful transitions between Mokap views.
Merge pull request #798 from RotaruDan/meaningfulTransitions

Meaningful transitions
IconWithPanel with scale refactoring. Created BaseIconWithPanel also improved show and hide animations.
Small MockupUI test improvements.
Removed unnecessary static field in IconWithPanel.
Small fixes to the transition process.
Improves DropDown widget with better animations.
Merge pull request #803 from RotaruDan/galleryStyle

Improved widget animations.
wip