Support installation of crx files
Some Markdown formatting cleanup.
(cherry picked from commit 6492417bdaa8b1eaa8fc44097c45e9f2c2897308)
Remove redundant and unused duplicate file, and improve Chrome loading

It now draws on the same Chrome app bootstrap files as exist in the app
harness itself. This ensures that the Javascript always matches the
native side.
Delete old copies of Chrome files from www/crx_files.

Only the config.platform.xml files are still used.
Update config.<platform>.xml files with modern format
Don't load the context menu until deviceready fires
Restyle to use Topcoat, popup notifications, and better UX.
Updating the README to reflect the modern state of the AppHarness.