Add support for Electron Framework

[andreimoldo]

Electron based apps are currently marked as Chrome (which is correct), but there needs to be a way to tell them apart.

[fnando]

Hello, @andreimoldo! This is your first Pull Request that will be reviewed by Ebert, an automatic Code Review service. It will leave comments on this diff with potential issues and style violations found in the code as you push new commits. You can also see all the issues found on this Pull Request on its review page. Please check our documentation for more information.

[fnando]

Similar code found in 7 other locations (mass = 21) (lib/browser/electron.rb#4, lib/browser/alipay.rb#4, lib/browser/firefox.rb#4, lib/browser/micro_messenger.rb#4, lib/browser/nokia.rb#4, lib/browser/phantom_js.rb#4, lib/browser/uc_browser.rb#4, and lib/browser/weibo.rb#4)

[fnando]

Ebert has finished reviewing this Pull Request and has found:

• 1 possible new issue (including those that may have been commented here).

You can see more details about this review at https://ebertapp.io/github/fnando/browser/pulls/305.