Blog Fragment in Navigation Drawer with Tabs

This replaces the custom layouts in the navigation drawer with a
`NavigationView` and adds a menu entry for Blogs.

A Main Blogs fragment is added that holds a `TabLayout` and a
`ViewPager`. Five tabs are already added, but they just have a single
placeholder fragment that is to be replaced by the actual fragments.

Closes #409

briar-android/src/org/briarproject/android/ActivityComponent.java

@@ -70,6 +70,12 @@ public interface ActivityComponent {
 	@Named("ForumListFragment")
 	BaseFragment newForumListFragment();
 
+	@Named("BlogsFragment")
+	BaseFragment newBlogsFragment();
+
+	@Named("MyBlogsFragment")
+	BaseFragment newMyBlogsFragment();
+
 	@Named("ChooseIdentityFragment")
 	BaseFragment newChooseIdentityFragment();