Add bottom margin in size of Navigation bar in case of full screen he…

…ight.

Fix setting texts.

Add Close help and Next item buttons.

Fix previous commit.

Add setTitleTextSize and setContentTextSize methods.

Fix previous

Add stop() to MaterialShowcaseSequence

Add methods getSequenceID() and isShowing() to MaterialShowcaseSequence

Add method showDismissButton to sequence.

- Update system components

- add showDismissButton() method