App Harness Work

[Andrew Grieve <ag...@chromium.org>]

Just finished up a batch of changes & updated the README.md for App Harness.

https://github.com/apache/cordova-app-harness

It now works with `cordova serve`, but I broke support for loading from
.cdvh (.zip) files. There's also a few UI enhancements, the data model no
longer requires you to give apps a name, and the context menu injection
code is less brittle.

It also puts the dependent "UrlRemap" plugin right in the repo (formally
"AppBundle").

The README has a list of missing features, so if anyone wants to jump into
it, now's a good time (it was a bit confusing to build before). Next time I
start making changes to it I'll be sure to make JIRA issues for the changes.

Andrew