add log output
1. Add BaseFragment and fragment status change listener
2. Change CaptureFragment extends from BaseFragment
3. Change MainActivity to implement fragment status change listener
4. Adjust the MainActivity logic to update fragment with persisted
PaletteData when the listener callback is triggered
refactor on TabsAdapter to change its structure recommended by google
android development guideline in view pager. see
http://developer.android.com/reference/android/support/v4/view/ViewPager.html
fix the issue that after rotate the screen the thumb is lost