Add horizontal rule format button to advanced and basic toolbar layouts

Author: theck13

aztec/src/main/res/layout/aztec_format_bar_advanced.xml

@@ -120,6 +120,15 @@
                 style="@style/FormatBarButton" >
             </org.wordpress.aztec.toolbar.RippleToggleButton>
 
+            <org.wordpress.aztec.toolbar.RippleToggleButton
+                android:id="@+id/format_bar_button_horizontal_rule"
+                android:background="@drawable/format_bar_button_horizontal_rule_selector"
+                android:contentDescription="@string/format_bar_description_horizontal_rule"
+                android:layout_height="fill_parent"
+                android:layout_width="wrap_content"
+                style="@style/FormatBarButton" >
+            </org.wordpress.aztec.toolbar.RippleToggleButton>
+
             <org.wordpress.aztec.toolbar.RippleToggleButton
                 android:id="@+id/format_bar_button_more"
                 android:background="@drawable/format_bar_button_more_selector"

aztec/src/main/res/layout/aztec_format_bar_basic.xml

@@ -123,6 +123,15 @@
                 style="@style/FormatBarButton" >
             </org.wordpress.aztec.toolbar.RippleToggleButton>
 
+            <org.wordpress.aztec.toolbar.RippleToggleButton
+                android:id="@+id/format_bar_button_horizontal_rule"
+                android:background="@drawable/format_bar_button_horizontal_rule_selector"
+                android:contentDescription="@string/format_bar_description_horizontal_rule"
+                android:layout_height="fill_parent"
+                android:layout_width="wrap_content"
+                style="@style/FormatBarButton" >
+            </org.wordpress.aztec.toolbar.RippleToggleButton>
+
             <org.wordpress.aztec.toolbar.RippleToggleButton
                 android:id="@+id/format_bar_button_more"
                 android:background="@drawable/format_bar_button_more_selector"