Input language switching. Bug: 2331173

New feature to enable fast switching between input languages for
multilingual users. Keyboard settings lets you select a bunch of
languages to switch between from the Latin IME.

Use the Globe icon to toggle between languages.

Needs more work and some layout changes in specialized keyboards.

Also added a Russian keyboard (needs some pixel TLC at the right edge).
diff --git a/res/xml/prefs.xml b/res/xml/prefs.xml
index 2fc82aa..d5075c5 100644
--- a/res/xml/prefs.xml
+++ b/res/xml/prefs.xml
@@ -37,6 +37,14 @@
             android:defaultValue="true"
             />
 
+    <PreferenceScreen
+            android:title="@string/language_selection_title">
+        <intent
+                android:action="android.intent.action.MAIN"
+                android:targetPackage="com.android.inputmethod.latin"
+                android:targetClass="com.android.inputmethod.latin.InputLanguageSelection" />
+    </PreferenceScreen>
+
     <PreferenceCategory
             android:title="@string/prediction_category"
             android:key="prediction_settings">