Feature/fixes to x6 workflow

[tanelkuhi]

1. Bring back activity editing from modal (our client strongly wanted this) - right clicking activity -> "Edit" opens it now
2. Recolor and move auto layout button away from add activity button
3. Fix the text for x6 usage instructions modal
4. Fix the test stats button clicking, so it would show the test info
5. Undo/Redo and copy-pasting are more reliable, since I made it work more like v3 does
6. Fix some other general issues

[dnfadmin]

All CLA requirements met.