v6.0.0 - Changelog + Version bump

[nickvergessen]

• Increase versions
• Add changelog to Changelog.md
• Add user changelog to Changelog Conversation

6.0.0 – 2019-MM-DD

Added

• Administrators can now define commands which can be used in the chat. See commands.md for more information #1453
• @all mentions all participants in the conversation #1531
• Allow to get the last sent message again with arrow-up #1520
• Conversations associated to files now have a link to the file #1387
• The Talk app can now be restricted to a group of users in the Talk administration settings #1585
• Show a warning when a call has many participants and no external signaling server is used #1649

Changed

• One-to-one conversations are now persistent and can not be turned into group conversations by accident. Also when one of the participants leaves the conversation, the conversation is not automatically deleted anymore. #1591 #1588
• Conversations must have a name now #1567

Fixed

• Fix multiple race-conditions that could interrupt connections, end calls or prevent connections between single participants #1522 #1533 #1534 #1549
• Use better icons when a file without preview or a folder is shared into the chat #1601
• Prevent issues when two participants share their screens #1571
• Correctly remember last media state when reloading in a call #1548 #5174
• Do not show conversation names and other details if the user is not a participant #1426 #1496 #1502