Implemented enhancements:
- Ubuntu iso got updated, MD5 check fails [#156]
- Improve rvd_front security [#180]
- Redirect admin user to admin machines if no bases [# 184]
- Add support Ubuntu for 17.04 (Zesty) [#187]
Fixed bugs:
- Check if name of new machine already exists [#38]
- ISO downloading prevents new domains creation [#176]
- ravada system user was not created on install [#179]
- Validate new machine name [#188]
- Fresh install missing virtual networks [#189]