SimpleX chat - v0.4.1 release

[epoberezkin]

• chat protocol use chat protocol and contacts in chat commands/messages #66
• user profiles establish connection using user profiles #69, update user profile (and notify contacts) #93
• chat groups started chat groups protocol #75, use shared namespace for usernames, contact names and group names #76, chat groups: establish connection between host and invitee members #77, core chat groups protocol for adding members #78, refactor groups #84, subscribe all user contacts and group members #85, group commands (remove member, leave group, delete group) #87
• merge contact profiles when existing contact is invited to group by another member merge profiles using contact probe #86
• asynchronous message delivery (messages can be sent when the client is offline) update for asynchronous message delivery #92
• send files to contacts #94
• send files to groups #97
• storing chat messages #91
• message delivery to pending group members
• update help - file transfer and groups #98
• docs
  • update readme #99
  • chat protocol
• group improvements:
  • show notification when member is connected to all members
  • message integrity based on Merkle DAG