Added methods to identify first and last scroll nodes.
Added scrolling on navigation.
set to perform scroll only if scroll is available.
Modified algorithm to allow highlighter to leave scrollable views.
Added scroll action when highlighter is outside of scrollable parent's view.
Merge branch 'develop' of https://github.com/idrc/tecla-framework into issue-136

Conflicts:
	package/tecla/keyboard/TeclaAccessibilityService.java
	package/tecla/keyboard/TeclaHUDOverlay.java
Resolved issue #70.
Merge pull request #181 from ericwan78/issue-136

fixes #136