add ActionBarCompat.setTitle() method

Now the title can be easily set in the ActionBar to reflect the current
Activity.

src/org/fdroid/fdroid/compat/ActionBarCompat.java

@@ -21,6 +21,7 @@ public abstract class ActionBarCompat extends Compatibility {
     }
 
     public abstract void setDisplayHomeAsUpEnabled(boolean value);
+    public abstract void setTitle(CharSequence title);
 
 }
 
@@ -34,6 +35,12 @@ class OldActionBarCompatImpl extends ActionBarCompat {
     public void setDisplayHomeAsUpEnabled(boolean value) {
         // Do nothing...
     }
+
+    @Override
+    public void setTitle(CharSequence title) {
+        // Do nothing...
+
+    }
 }
 
 @TargetApi(11)
@@ -50,4 +57,9 @@ class HoneycombActionBarCompatImpl extends ActionBarCompat {
     public void setDisplayHomeAsUpEnabled(boolean value) {
         actionBar.setDisplayHomeAsUpEnabled(value);
     }
+
+    @Override
+    public void setTitle(CharSequence title) {
+        actionBar.setTitle(title);
+    }
 }