3822 android

#3822 is for revamping each Getting Started Guide, eventually to be retitled SDK Guides. This branch covers a complete rewrite for Android.  Two commits for start/end of section. Please review before committing. E.g. prior doc says support for Android 2.1 & 3.x are deprecated as of May 2013. Modified install details based on a clean vanilla SDK build. Changed details of emulator setup to rely on SDK's built-in AVDs. Removed references to low-level CL tools superseded by CLI.  Where appropriate, provided alternate instructions for emulate/run from CLI & SDK. Added newly cut screen shots for emulator setup. Relaxed the doc by removing heavily nested headings & lists. Consider this a template for how each platform's SDK Guide will appear.