add the screenshots used on chrome extension page
Additive color, options page live view, bug fixes

* Add additive color version of the histogram
* Make the options page show an example that updates as you change
options
* fix an odd issue where chrome will say the clickSrc is undefined.
I've only seen this come up when the image is the page source, so treat
request.clickSrc == undefined as applying to the clicked element
fix needing to reload content page when extension reloads

Listen for the onDisconnect and nullify port so the next "info" request
will cause a new connection
better organize the options page