Command Palette for Firefox per djwj

Control Firefox with Sublime Text style fuzzy complete. It can be used from the omnibar with the ; search prefix, or trigger a pop-up with Ctrl+Space (the keybinding is configurable).

Currently, it supports the following functionality:
- Create, navigate, reload and close tabs.
- Reopen current tab in a different container.
- Create tabs in temporary containers.
- Pin and unpin tabs.
- Mute and unmute tabs.
- Put current, or all other tabs to sleep.
- Move current tab to a new window.
- Pop the current tab into it's own window with minimal UI.
- Toggle reader mode in the current tab.
- Save the current tab as a PDF.
- Open a new window.
- Open a new private window.
- Close the current window.

This extension is a work-in-progress - expect bugs. Issues and pull requests are welcome on Github.