make sure only first path in list of build/install/source paths is attempted to be created
remove block of code to create (only) first build/install/source path, enhance unit tests
drop new config.py unit test, enhance new toy build unit test instead
remove unused internal function create_dir
Merge pull request #888 from boegel/fix_creating_new_path

make sure only first path in list of build/install/source paths is attempted to be created