Modified the project structure, removed module extension and went instead for a non-complete core dependency graph

Semi-encapsulated the core/api dependency graphs and created a proper structure to load eager singletons

Includes code from https://github.com/consp1racy/android-support-preference
License: Apache License v2.0

This commit renames identicons to avatars in field names, and uses an ImageView
derivative to show the identicons, which should make implementing #214 easier.

Also removed unnecessary adapter notifications in various places.