- display a popup for selecting/deselecting registered repositories

(to allow e.g. disabling Updates and installing GA version)(FATE#312012)

- 3.1.18
save the user changes and and revert them back at the and of installation

in new `scc_finish` client
code review fixes

- :live_installation support
- rename activate to restore_state
- fully qualify ::Restore call
raise error in scc_finish client on wrong usage
scc_finish - better handle script parameters
improved scc_finish_test
use ::Registration to be sure there is no collision in Yast namespace
Merge pull request #24 from yast/select_repos

Display a popup for selecting/deselecting registered repositories