Moderation and Stickers * Unify new contact and new channel into one dialog * Do not require adding a contact to message or call * Allow moderators to moderate messages in channels * Hide avatar, nickname, and content for moderated messages in channels * Don't change XMPP URI link labels if they have a custom one via XHTML-IM * If an XMPP URI is for the current conversation, hide redundant display name * Unread count should use primary colour (possible from custom colour theme) * Sleep hack to make "all done" notification for backups more reliable * Allow blocking avatars and other media by hash locally * Offer to download default sticker packs, storing CID and URL * Send CID with known URL without uploading * Send SIMS with hashes and filename * Allow importing stickers made for Signal (via signal.art or sgnl:// links) * Allow command UI cancel even if an embedded webpage is broken * Fixes for older Android version compatibility * Fixes for various crashing bugs