Initial import. Partially completed Push.java

This is being saved before I fork it to try out NanoHTTPD instead.
Working HTTP server version
Fixes to Push code. Now navigating from Javascript.
Initial import of the makeharness script.
Add README and LICENSE files.
Update wording of README.
Working /push. Add /exec and /menu.

- Currently only cordova serve pushes are supported:
    /push?type=serve&name=<appname>&url=<serve URL>
- Run arbitrary Javascript in the app:
    /exec?code=<JS code, be careful of HTML encoding>
- Return to the main App Harness menu:
    /menu
Adding LICENSE and README.
Markdownify the LICENSE more fully.
Now with push support for crx files
Adding BarcodeScanner plugin.
Add a necessary manual step to README.md
Enhancements to makeharness.sh and add .gitignore
Update README.md now that there are fewer manual steps.
Tweak README.md example
Merge harness-push plugin into this repo.
Don't inject harness-push JS on iOS
Add getListenAddress() to harness-push
Use webView.loadUrlIntoView() for reload instead of window.location
Add manual step of changing title to README.md