Fix login persistence issue
Fix startup crash accessing uninitialized instance

Introduced by previous commit.
Fix logout screen hanging
Manage account with AccountManager
Log in to app with stored account

The AccountManager is used to store the user's account on the phone if they choose to be remembered.
If the account is on the phone, the user will be logged in automatically.
If the user logs out of the account, it will be destroyed.
Abstract getting feed
Merge branch 'login-persistence' of github.com:swiggins83/uMobile-Android-App into swiggins83-login-persistence

Conflicts:
	app/src/main/java/org/apereo/activities/LoginActivity.java
Merge branch 'swiggins83-login-persistence'