Created by: WendellDuncan
PR checklist
[X ] Read the contribution guidelines.
[ X] Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
[X ] Filed the PR against the correct branch: master, 3.4.x, 4.0.x. Default: master.
[X ] Copied the technical committee to review the pull request if your PR is targeting a particular programming language.Description of the PR
This add polymorphic support for the cpp Qt5 client. Issue #1345