fix Firefox unread count bug
update CHANGELOG.md
Release 4chan X v1.8.6.2.
Merge tag 'beta' into unreadcount

4chan X v1.8.7.

Conflicts:
	CHANGELOG.md
	LICENSE
	builds/4chan-X-beta.crx
	builds/4chan-X-beta.meta.js
	builds/4chan-X-beta.user.js
	builds/4chan-X-noupdate.crx
	builds/4chan-X-noupdate.user.js
	builds/4chan-X.crx
	builds/4chan-X.meta.js
	builds/4chan-X.user.js
	builds/4chan-X.zip
	builds/updates-beta.xml
	builds/updates.xml
	package.json
Release 4chan X v1.8.7.1.
Merge branch 'unreadcount'

age to explain why this merge is necessary,