No sharedprefs methods in ConfigHelper.

This means we obtain the SharedPreferences object each time we want to
use it. This yields to longer code lines while reading and writing to
them.
Substituted AboutFragment with AboutActivity.
Merge branch 'feature/remove-shared-preferences-methods-from-ConfigHelper' into develop

Conflicts:
	src/se/leap/bitmaskclient/Dashboard.java
Merge branch 'bug/about-fragment-legacy-references' into develop