Bugfixes on probing

[breiler]

Fixes for a couple of bugs on probing:

• Fixed problem with setting enable which can't be done in the event thread causing exceptions
• Added a tooltip that describes how the retract amount works
• Shows/hides the probing/autoleveling preview when the component is shown
• Fixed the wrong mapping of X -> Y value in autoleveler
• Fixed problem with equals matching doubles, lowered the precision.
• Fixed problem with concurrent updates to list of renderables