JsonPreprocessor need to return a dotdict

[test-fullautomation]

JsonPreprocessor need to return a dotdict (always be aware that a user can use python-jsonpreprocessor without testsuitesmanagement).
Only problem is that dotdict of JsonPreprocessor is other than the one used by Robot Framework.
Therefore testsuites-management need to do a conversion to Robot Framework's dotdict.
Thank you,
Thomas

Originally posted by @test-fullautomation in #245 (comment)

[namsonx]

Hello Thomas,

This enhancement is available on stabi branch.

Thank you,
Son