New Feature: Security PIN on startup.
BUG FIX:
* Changed initial PIN screen to be displayed before the HomeScreen is shown instead of over it.

CHANGES
* Changed name of Preference for the pinCode

Notes:
HomeScreen really does not like other screens popping up over it too early.
BUG FIX:
Fix PIN screen facade not getting closed correctly.

For some reason, calling .Close() from within the Activate routine would
not end up sending a isScreenClosed() message.
Missed one place for changing the preference name.
Merge pull request #80 from wagnerscastle/test

New Feature: Security PIN to lock channel