Created by: ousenko
This fixes the issue #174.
How DemoActivity handles the ActionBar appearance is a bit inconsistent - getActionBar.hide() and setActionBarTranslation(float) in no way lead to the same ActionBar state. Thus, a call to getActionBar.hide() should be replaced to the latter.
!getActionBar().isShowing() in onSaveInstanceState(Bundle) always result to false, thus the ActionBar is considered shown even if a panel is expanded, and is not hidden on orientation change.
I made SlidingUpPanelLayout a class member variable, which allows to check its state in onSaveInstanceState(Bundle).
When restoring the state, if we consider that ActionBar should be hidden, then we call setActionBarTranslation( - actionBarHeight ), thus moving away the ActionBar.