Install Portage using setup.py
travis: Use setup.py for running tests
Revert "Merge branch 'new-install' into all-in-one-plus-setup.py"

This reverts commit 39c6d8fc11bd9edc87f636e0e550dc6aa452a379, reversing
changes made to 065fbb428c4738fbbababfe089684ddca07ec023.
Merge branch 'new-install' into all-in-one-plus-setup.py