Stopwatch widget for timingandestimationplugin

Summary

The TaE maintainer, Russ, has been very positive about this widget. At the time of writing, he is working to include it in the main TaE repo/distribution.

In the meantime, you can get this in two ways:

1. The 'master' branch, which is a ready-for-install replacement of TaE 0.11.

2. The 'export' branch, which has adds/replaces files in TaE.

Files (new/modified)

README.md
setup.py
timingandestimationplugin/api.py
timingandestimationplugin/htdocs/StopwatchControls.js
timingandestimationplugin/htdocs/StopwatchDisplay.js
timingandestimationplugin/htdocs/Toggler.js
timingandestimationplugin/htdocs/stopwatch.js
timingandestimationplugin/stopwatch.py