Fix crash analysis and save load reaction

Avoid warnings when save/Load LidarState in stream mode
The properties Start and Stop of the Stream are "vtkSMProperty".
Casting it into a proxy property raises a warnings that can be confusing for the user.

Fix crash of "Is crash Analysing" option in stream mode
During "CrashAnalysing" option:
If the directory can not be created boost::filesystem raises an error and the application crash.
We add a try{} catch{} to avoid that.