[firefox] Use an iframe as the window

Instead of polluting the base hiddenDOMWindow, use an iframe.
[firefox] Convert to bootstrapped extension

 1. Restartless install (closes #89)
 2. Start at launch (closes #38)
[firefox] Add options button to addons page.
added click-to-filter to tags; cursor becomes pointer when hovering over
tags
Don't add special cases to the note onClick method
Merge pull request #93 from HaleyB-E/clickTags

Clickable tags closes #93
Refactor Icons.