fix crash if disconnect happens for sessions that have messages queued
remember user session because it can be gone when finalHandler is called
changelog, package file and fix for redo
Merge pull request #2092 from webzwo0i/fix-crash-with-queued-messages

Fix crash with queued messages
Polish the styles of our docs a little
Merge pull request #2117 from ether/doc/asset-css-suit-up

Polish the styles of our docs a little
fix error on focus remove from import/export
Fix timeslider export dropdown
Create a customizable timeslider toolbar
Fix redo toolbar command, again.
Update docs
Merge pull request #2120 from ether/fix/timeslider-editbar

Add a customizable toolbar for timeslider