restructure the directory structure

* move library code into src directory
* move tests from Tests to tests directory
renamed GitHub repository from xabbuh/PandaClient to Xabbuh/panda-client
[WIP] serializer implementation
[WIP] serializer implementation
move Serializer to src directory too
Merge branch 'serializer-component' of github.com:xabbuh/PandaClient into serializer-component
fix tests namespace directories, refactor tests