wxwidgets.cfg: Add container configuration for wxString

[versat]

Reference: https://docs.wxwidgets.org/3.0/classwx_string.html

[versat]

I checked the wxString container configuration with the Boinc project sources that use wxWidgets and I can not see false positives/negatives. There are now passedByValue messages like they are issued for std::string, but that seems valid.
@orbitcowboy Do you have time to test this configuration against some projects or verify the changes directly? You are working on the wxwidgets.cfg so I just guess you have some projects for testing wxWidgets stuff :) If not we can let daca@home test it and see how it performs.

[orbitcowboy]

I checked the wxString container configuration with the Boinc project sources that use wxWidgets and I can not see false positives/negatives. There are now passedByValue messages like they are issued for std::string, but that seems valid.
@orbitcowboy Do you have time to test this configuration against some projects or verify the changes directly? You are working on the wxwidgets.cfg so I just guess you have some projects for testing wxWidgets stuff :) If not we can let daca@home test it and see how it performs.

Many thanks for adding this configuration. This was already on my list too :-)
I have tested your PR with my wxWidgets projects and i did not see any effect. The results did not change.

Feel free to merge your PR after CI is OK. Then we can observe daca@home results.

[versat]

Thanks for testing.
Master has issues currently that need to be resolved first, then a Travis analysis can be triggered again.
No changes in the results for your projects sounds good I guess. Then there should not be too many false positives/false negatives :)