fix PyLD to version < 2.0 in package setup
Add new get_mentions helper
Tweak the user agent
Tweak recipients handling
Loosen HTTP sig keyID verification
support HTTP 406
fix PyLD to version < 2.0
handle 403 as ActivityUnavailableError
Fix tests
More HTTP sig tweaks
Update HTTP sig tests
Improve HTTP sig (for misskey)
Add Page support
Fix formatting
Re-add the HTTP sig check in the right place
Remove un-needed check
Fix typo
Fix HTTP signatures
Cleanup the new helper
Add new get_in_reply_to helper