Convert Firefox to Web Extension

[PxlBuzzard]

Firefox now accepts Web Extensions.

[PxlBuzzard]

This work was completed in v1.4.6

[FichteFoll]

Unfortunately, the .xpi on the releases page is unsigned and FF just redirects me here instead of installing it.

[PxlBuzzard]

I have a task to create an unofficial release of the Firefox addon that will be compatible with Firefox v48+. I would prefer to add it to Firefox Addons so we can more easily distribute updates going forward, but the Addon gatekeepers want a non-insignificant refactor before letting it onto the store (see #88). I will post the new .xpi file in the main Firefox issue once that's ready to go.

[FichteFoll]

Thanks for the heads up. I was looking for a separate FireFox issue, but none of the open issues' titles hinted anything. I'll follow #88 for now.

(I also now remember that it was being mentioned in #33 as well.)