Use `importlib.import_module` instead of `__import__`

Given that python 2.6 support is going to be dropped, the recommended way to import modules is using `importlib.import_module` as stated in the `__import__` doc:

    Import a module. Because this function is meant for use by the Python
    interpreter and not for general use it is better to use
    importlib.import_module() to programmatically import a module.



PD: Sorry for the typo in the second commit!