Perform app updates in background

[blazsolar]

Checking for app updates should also be moved to background instead of doing it on every activity launch. They should be perform when user is on WiFi and charging so we don't impact users battery and network bill.

http://evernote.github.io/android-job/

[aldoborrero]

For this I suggest using Android job by Evernote. It uses JobScheduler API for modern versions and GcmNetworkManager for older versions.