Add methods to run commands and copy files to Host objects. Adds a base class for integration tests which can currently install and uninstall IPA in a "star" topology with per-test specified number of hosts. A simple test for user replication between two masters is provided. Log files from the remote hosts can be marked for collection, but the actual collection is left to a Nose plugin. Part of the work for: https://fedorahosted.org/freeipa/ticket/3621