Add popup blocker settings to the Chrome extension build

[ameshkov]

This is a pre-requisite for the Chrome extension release.

Here's how I see it

1. Use the options_ui to add a settings page;
2. Add an options.js file that will make that page alive. It should rely on an OptionsController object, that will be injected externally. Therefore, you'll be able to reuse both options.html and options.js in the userscript.

In the userscript's case, the options page will be located on GH pages. The userscript will detect that it's loaded on a settings page and will inject its own OptionsController implementation.

[ameshkov]

Done