Initial port of the acceptable use tutorial from iOS app. This version uses static images and is not yet animated. Indicator circles on the pager are done using Apache-licensed https://github.com/JakeWharton/Android-ViewPagerIndicator -- imported via maven. Currently the tutorial launches when we reach the login screen (as when first installing the app or creating a new account from system settings). You can either 'back' out of it or page through and hit the 'yes' button.
GitHub: https://github.com/wikimedia/apps-android-commons/pull/20
Change-Id: Ibc444102e28a55bfa7bbae601ff0c56268a0c7dd
