Android: Update docs for auto import.

Android studio requires additional configuration to enable automatic
imports on the fly.

Also fix some markdown formatting, 4-space tabs necessary for sublists.

BUG=667858

Review-Url: https://codereview.chromium.org/2530903003
Cr-Commit-Position: refs/heads/master@{#434370}
1 file changed