Reverting to old blockchain code

The notification code requiring the new support library broke
the app in production.  Going back to the way it was, but keeping
all the other changes to the app.  Production ready signed APK
tested on one of my devices.
3.30.6
Fixing crash on empty scan

When scanning on one of my phones I ran into this issue when hitting
back without scanning anything.  A quick null check solves the issue,
and it functions normally now.