for screen density and system version.
Add section about providing compatibility for multiple devices
bug: 2760561
Change-Id: I9b3a515a14d53923a15b1931f6dd24f295874362
docs: rewrite resources documentation
Huge overhaul. Includes all new dev guides about how resources are used
on Android and how to provide alternatives, including how to handle
runtime configuration changes (restarts). Plus all new reference
docs for all the resource types (drawables, strings, menus, etc.).
Change-Id: I12e819d2c5fc11e062281d8fe442c3037e92000a
