* [#629] [test] volatiles are removed from front

* [#629] [test] check volumes are removed

* [#629] check volumes are removed after shutdown

* [#629] force volume removal after shutdown of volatile

* [#629] test XML in extra data is there

* [#629] Allow forced virtual machine open

It will open even if there is no real virtual machine
in the VM

* [#629] store extra information of the virtual machine

Each different VM can have extra fields only for its kind

* fix: clean iptables even if domain removed

[#629]

* fix: remove domain even it is not known

[#629]

* wip(backend): remove disks from volatile clones

issue #629 wip

* feat(backup): clean temporary machines volumes

issue #629

* test(volatile): check volatile volumes are removed

* fix(downloads): retry if download failed

* fix(volatile): clean requests on machine remove

issue #629