Add multidex library and extend CommonsApplication from MultiDexApplication.

Fixes commons-app#1225

Author: knight-shade

app/build.gradle

@@ -48,6 +48,8 @@ dependencies {
     compile 'com.facebook.fresco:fresco:1.3.0'
     compile 'com.facebook.stetho:stetho:1.5.0'
 
+    compile 'com.android.support:multidex:1.0.2'
+
     testCompile 'junit:junit:4.12'
     testCompile 'org.robolectric:robolectric:3.7.1'
 

app/src/main/java/fr/free/nrw/commons/CommonsApplication.java

@@ -4,6 +4,7 @@
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.database.sqlite.SQLiteDatabase;
+import android.support.multidex.MultiDexApplication;
 
 import com.facebook.drawee.backends.pipeline.Fresco;
 import com.facebook.stetho.Stetho;
@@ -40,7 +41,7 @@
         resDialogCommentPrompt = R.string.crash_dialog_comment_prompt,
         resDialogOkToast = R.string.crash_dialog_ok_toast
 )
-public class CommonsApplication extends Application {
+public class CommonsApplication extends MultiDexApplication {
 
     @Inject SessionManager sessionManager;
     @Inject DBOpenHelper dbOpenHelper;