Prepare for release.

- Add splash screen
- Refactor UI
- Remove logback
- Add Bugfender for remote logging/debugging
- Use Realm.io for locally storing data
- Don't require an Internet connection to poll and store data locally
- Improve setup flow
- Add the beginnings of a Status activity
- Change device poll and upload tasks to be IntentServices

- Refactor UI (use Material Design and new font, drop to single style.xml)
- Do the pump comms using an IntentService in a separate thread
- Add extra OTG check
- General clean up and refactoring (improve naming and code).

Code cleanup and minor refactoring to improve maintainability and the ability to internationalise the app.
Fixes #43

Fix #16 - show registered USB sticks in the registration activity
Fix #14 - show successfully registered devices after CareLink login.

Make only the log part of the UI scrolls.

Fix #6

Remove hardcoded keys.

Removed all options to use Dexcom or Medtronic CGM (sorry arbox0).