* Message with multiple mentions are not broken in IRC. Fix#267
* Editing a message won't remove mentions anymore
(cherry picked from commit bb3b3bc088)
Now it will save a map from display name to id and use that to generate
clean matrix.to links. This also make sure the colors used for the
preview are correct by using NeoChatUser and fix the bug with the regex
by simply removing the regex.
Fix#234