0686591b8c
This introduces two new docs: Application Fundamentals: This is the homepage for the app fundamentals; it introduces the security sandbox, each of the component types, intents, the manifest file, and app resources. Processes and Threads: Most of this document is from the original fundamentals.jd doc; it describes more about how an app's process runs on android and the different levels of process importance used to determine which processes the system can kill and how threads are and should be used in an application. I've added more detailed information about threads, however, including information about using AsyncTask. These documents are orphaned for now. This is the last set of documents required before I'll change the side navigation to adopt the new app fundamentals and redirect the old fundamentals.jd file. Change-Id: Ie0c6540a3a6d86780718e2918b8dffcda37d925c