cherrypick Change-Id: I1365c6c45f8e1f75ee4afbc52c32778d21b97be4 from master

docs: Rewrite of App Fundamentals.. Part 2.
This introduces three new docs:

Services:
  Provides an introduction to using services and describes the
  service lifecycle (previously in the "Component Lifecycles" section
  of the fundamentals.jd document)
Bound Services:
  A guide for services that offer binding.
AIDL:
  A doc about using AIDL (primarily for creating a service interface)

Also includes edits to IntentService javadocs to clarify
different behaviors for some callback methods

Includes a new version of the services lifecycle diagram
and an additional diagram for determining onRebind()

These files are orphaned for now---they're not linked in the sidenav,
until I get the last couple documents submitted for the app fundamentals.

Change-Id: I7fb0a8faff1f18b7d6b9a7b59f66f55a1b6168f1