Tests modified to comply with PEP8 rules with exception of rule E501 (long lines).
Done by autopep8 tool and 2 manual modifications.
https://fedorahosted.org/freeipa/ticket/3744
Heavily inspired by code from xmlrpc tests.
To obtain ranges, this patch also adds method to execute FreeIPA command through Web UI.
It uses Web UI instead of ipalib so it doesn't need to care about authentication on a test-runner machine.
https://fedorahosted.org/freeipa/ticket/3744