Live Editing - Page specific features

[fungairino]

Page Editor e2e tests to cover that relate to edge specific page edge cases

• Special Page Detection
  • Verify that a special page is shown if the target page is the extension console page, or an internal chrome page.
• Reload Message
  • “Reload” message is shown over the whole page editor when changes are made in the background.
    • Ex. clicking on an activation link.
• Unavailable Mod Indicator
  • “Not available on the page” icon in the mod listing panel when the mod would not be run for the target URL.