Add `@grant` back

When I implemented grunt, this is the only header that didn't get
transferred. Surprised that it even worked without it.
Update screenshot
Added base debug info.

Activated by visiting any Twitch page and adding
`#twitch-chat-emotes-debug` to the end of the URL.
Allow non-`chansub` emotes

This opened an opportunity to change the logic behind how getting usable
emotes works. Checks emote URLs instead of relying on `emoticon_sets`.
Fixes an error on non-standard subscription channel names. Fixes #20 as
`userInfo.emoteSets` is no longer used.
Version bump