the wheel moves the Logs

Works only if the mouse hit a log
_children is not modify
The scrolling is now limited
Update the scrolling

it bug when collapse
log disappear sometimes cause they are remove from _children
scrolling working, minor problem has to be resolve

the mouse has to hit a log to move them
the user don't see the logs disappears
Fix & upgrade

- ILogEntry implementations ARE internal!
- Upgrade to CK.Core 2.8.14
Merge branch 'f-scrolling' into f-Viewer
Filter the logs

Print a line at the place of the logs filtered
Merge remote-tracking branch 'origin/f-LogLevelFilter' into f-Viewer