Feature/groups (#71)

* Basic group management

* Assign cards to groups

* Fix lint

* Fix findbugs 'dodgy code'

* Group name as unique key

* More group tests

* Import/export groups

* Implement group renaming and deleting

* Fix findBugs

* Fix chip marking in edit activity

* Group import/export tests

* Fix some state bugs

* Some last fixes

* Remove redundant if statement

* Fix findBugs

* Deduplicate code

* Cleanup

* Fix groups not showing up with new card

* Fix capture and enter button touching

* Fix dialog button look

app/src/main/java/protect/card_locker/LoyaltyCardViewActivity.java

@@ -1,6 +1,5 @@
 package protect.card_locker;
 
-
 import android.content.Intent;
 import android.content.pm.ActivityInfo;
 import android.graphics.Color;
@@ -34,7 +33,6 @@ import com.google.zxing.BarcodeFormat;
 
 import protect.card_locker.preferences.Settings;
 
-
 public class LoyaltyCardViewActivity extends AppCompatActivity
 {
     private static final String TAG = "Catima";