Rewrite of Remote Smart Card Reader

- use material design
- use AsyncTask instead of Runnable for VPCDWorker to integrate with the
  App's lifecycle
- use a dedicated Preference Activity
- integrated zxing's QR code scanner
- use Snackbar instead of Toast
- capture debug messages in log instead of explicitly passing messages
- use reader mode only, breaks support of Android before kitkat

remote-reader/.gitignore

@@ -0,0 +1,8 @@
+*.iml
+.gradle
+/local.properties
+/.idea/workspace.xml
+/.idea/libraries
+.DS_Store
+/build
+/captures