Add flags to common.bazelrc and register toolchains in bazel.WORKSPACE to integrate the Bazel Android rules.
Test: Built example Android app in build/bazel/examples/android_app.
Change-Id: I5012541d1b2ab699c740700c36cec606702f3ab1
The code in this directory is experimental. Bazel support for Android Platform is undergoing active development and workflow stability is currently not guaranteed.