use resolve(allow_erasing=True), new API in Dnf 0.5.0
Use new package_* api from dnf 0.5.0
build: req. dnf >= 0.5.0
more use of package_* api
call succes_finish() if RunTransaction is completted without errors
tests: make GroupInstall test work even if firefox group is already installed
use the dnf 0.5.0 group API
fix group tests, so they enable all repos and runs faster
Run with local dnf checkout build
save the groups if do_transaction return rc == 0
tests: make GroupInstall more error prone
tests: split up system tests in ro & rw
renamed Makefile test targets with run-test prefix