Add preference for SMS invitation prompt

// FREEBIE

res/values/strings.xml

@@ -1192,7 +1192,8 @@
     <string name="preferences_chats__chats">Chats</string>
     <string name="preferences_notifications__message_notifications">Message notifications</string>
     <string name="preferences_notifications__events">Events</string>
-
+    <string name="preferences_chats__show_invitation_prompts">Show invitation prompts</string>
+    <string name="preferences_chats__display_invitation_prompts_for_contacts_without_signal">Display invitation prompts for contacts without Signal</string>
 
 
     <!-- **************************************** -->

res/xml/preferences_chats.xml

@@ -30,6 +30,12 @@
     <PreferenceCategory android:layout="@layout/preference_divider"/>
 
     <PreferenceCategory android:title="@string/preferences_chats__chats">
+        <org.thoughtcrime.securesms.components.SwitchPreferenceCompat
+                android:defaultValue="true"
+                android:key="pref_show_invite_reminder"
+                android:title="@string/preferences_chats__show_invitation_prompts"
+                android:summary="@string/preferences_chats__display_invitation_prompts_for_contacts_without_signal" />
+
         <org.thoughtcrime.securesms.components.SwitchPreferenceCompat
                 android:defaultValue="false"
                 android:key="pref_system_emoji"

src/org/thoughtcrime/securesms/ConversationActivity.java

@@ -979,6 +979,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
   protected void updateInviteReminder(boolean seenInvite) {
     Log.w(TAG, "updateInviteReminder(" + seenInvite+")");
     if (TextSecurePreferences.isPushRegistered(this)      &&
+        TextSecurePreferences.isShowInviteReminders(this) &&
         !isSecureText                                     &&
         !seenInvite                                       &&
         recipients.isSingleRecipient()                    &&

src/org/thoughtcrime/securesms/util/TextSecurePreferences.java

@@ -79,6 +79,7 @@ public class TextSecurePreferences {
   private static final String SIGNED_PREKEY_ROTATION_TIME_PREF = "pref_signed_pre_key_rotation_time";
   private static final String IN_THREAD_NOTIFICATION_PREF      = "pref_key_inthread_notifications";
   private static final String BLOCKING_IDENTITY_CHANGES_PREF   = "pref_blocking_identity_changes";
+  private static final String SHOW_INVITE_REMINDER_PREF        = "pref_show_invite_reminder";
 
   private static final String LOCAL_REGISTRATION_ID_PREF       = "pref_local_registration_id";
   private static final String SIGNED_PREKEY_REGISTERED_PREF    = "pref_signed_prekey_registered";
@@ -487,6 +488,10 @@ public class TextSecurePreferences {
     setBooleanPreference(context, REGISTERED_GCM_PREF, registered);
   }
 
+  public static boolean isShowInviteReminders(Context context) {
+    return getBooleanPreference(context, SHOW_INVITE_REMINDER_PREF, true);
+  }
+
   public static boolean isPassphraseTimeoutEnabled(Context context) {
     return getBooleanPreference(context, PASSPHRASE_TIMEOUT_PREF, false);
   }