Navigation drawer, Android 4.3_r1, support-v4 r18.

Provides navigation drawer support back to API 7 on par with the Android 4.3 implementation.  [`setHomeActionContentDescription()`](http://developer.android.com/reference/android/app/ActionBar.html#setHomeActionContentDescription\(java.lang.CharSequence\)) only has an effect on Android 4.3.  This behavior is identical to the official support implementation.

See the ABS demo [Navigation Drawer](https://github.com/jameswald/ActionBarSherlock/blob/navigation-drawer/actionbarsherlock-samples/demos/src/com/actionbarsherlock/sample/demos/NavigationDrawer.java) for a working example.  In this particular demo, you may notice that the selected item's background will only be highlighted on Honeycomb+.  This is due to the use of the built in [activatedBackgroundIndicator](http://developer.android.com/reference/android/R.attr.html#activatedBackgroundIndicator) added in v11.  It may be replaced with custom drawables to support all platforms.

This implementation makes use of [`ActionBarDrawerToggle.Delegate`](http://developer.android.com/reference/android/support/v4/app/ActionBarDrawerToggle.Delegate.html) and [`ActionBarDrawerToggle.DelegateProvider`](http://developer.android.com/reference/android/support/v4/app/ActionBarDrawerToggle.DelegateProvider.html) added in support-v4 r18.  The Android training guide [Creating a Navigation Drawer](http://developer.android.com/training/implementing-navigation/nav-drawer.html) is still based on r13 and has not yet been updated for r18.  In addition to the training guide, your Activity class must implement `ActionBarDrawerToggle.DelegateProvider` and should replace the use of [`ActionBarDrawerToggle`](http://developer.android.com/reference/android/support/v4/app/ActionBarDrawerToggle.html) with the [`SherlockActionBarDrawerToggle`](todo) & [`SherlockActionBarDrawerToggleDelegate`](todo) convenience classes (see the ABS demo).  Alternatively, you may implement your own toggle and toggle delegate classes.

This cannot be made available for general use until Google publishes Android 4.3_r1 and support-v4 r18 on a public Maven repository.  Until then, this change will prevent ABS from building without additional efforts to get the Android 4.3_r1 and support-v4 r18 dependencies installed in your local Maven repository.