Android Support Library, revision 18 (July 2013)

Changes for v4 support library:
  - User interface
    - Added BidiFormatter [1] for handling text strings that combine right to left and left to right-formatted text.
    - Modified ViewPager [2] to better handle cases where the pager has a measured width of zero in the initial layout processing.
    - Modified DrawerLayout [3] and SlidingPaneLayout [4] to not throw exceptions for measurement while the project code is being edited.
  - Accessibility
    - Added ExploreByTouchHelper [5] to simplify the implementation of accessibility for custom views.
    - Fixed a problem with ViewPager [2] incorrectly populating TYPE_VIEW_SCROLLED [6] accessibility events.
    - Fixed a null pointer exception in ViewPager [2] when populating an accessibility event.
    - Simplified AccessibilityNodeInfoCompat [7] by changing CharSequence [8] inputs to String [9] objects.
    - Deprecated an AccessibilityRecordCompat [10] constructor that used an Object [11] as input.
  - Media
    - Added TransportMediator [12] helper class to manage media transport control, such as play, pause, skip and other media actions.
    - Added DisplayManagerCompat [13] for managing display output to one or more device displays.
  - Other changes
    - Added WakefulBroadcastReceiver [14] helper class for implementing
      a common pattern of detecting a device wakeup event and passing work off to a Service [15] while ensuring that the device does not go back to sleep before the handoff is complete.
    - Added two new APIs, commitContentChanged() [16] and rollbackContentChanged() [17], to AsyncTaskLoader [18] to help deal with background updates for data changes that are subsequently canceled.

New v7 appcompat library:
  - Added ActionBar [19] to allow implementation of the action bar user interface design pattern [20] back to Android 2.1 (API level 7) and higher. Use of this class requires that you implement your activity by extending the new ActionBarActivity [21] class.

 [1] http://developer.android.com/reference/android/support/v4/text/BidiFormatter.html
 [2] http://developer.android.com/reference/android/support/v4/view/ViewPager.html
 [3] http://developer.android.com/reference/android/support/v4/widget/DrawerLayout.html
 [4] http://developer.android.com/reference/android/support/v4/widget/SlidingPaneLayout.html
 [5] http://developer.android.com/reference/android/support/v4/widget/ExploreByTouchHelper.html
 [6] http://developer.android.com/reference/android/support/v4/view/accessibility/AccessibilityEventCompat.html#TYPE_VIEW_SCROLLED
 [7] http://developer.android.com/reference/android/support/v4/view/accessibility/AccessibilityNodeInfoCompat.html
 [8] http://developer.android.com/reference/java/lang/CharSequence.html
 [9] http://developer.android.com/reference/java/lang/String.html
[10] http://developer.android.com/reference/android/support/v4/view/accessibility/AccessibilityRecordCompat.html
[11] http://developer.android.com/reference/java/lang/Object.html
[12] http://developer.android.com/reference/android/support/v4/media/TransportMediator.html
[13] http://developer.android.com/reference/android/support/v4/hardware/display/DisplayManagerCompat.html
[14] http://developer.android.com/reference/android/support/v4/content/WakefulBroadcastReceiver.html
[15] http://developer.android.com/reference/android/app/Service.html
[16] http://developer.android.com/reference/android/support/v4/content/Loader.html#commitContentChanged()
[17] http://developer.android.com/reference/android/support/v4/content/Loader.html#rollbackContentChanged()
[18] http://developer.android.com/reference/android/support/v4/content/AsyncTaskLoader.html
[19] http://developer.android.com/reference/android/support/v7/app/ActionBar.html
[20] http://design/patterns/actionbar.html
[21] http://developer.android.com/reference/android/support/v7/app/ActionBarActivity.html