SO3Group organization and repo restructuring

You may notice that github.com/SO3Group organization is gone. There is nothing horrible going on, I just merged it with github.com/vyos organization for convenience.

The following changes were made:

• github.com/SO3Group/vyatta-cron is removed, it was an outdated version of github.com/vyos/vyatta-cron
• github.com/SO3Group/vytest is now github.com/vyos/vytest
• github.com/SO3Group/ipaddrcheck is now github.com/vyos/ipaddrcheck
• github.com/SO3Group/emrk is now github.com/vyos/emrk

There will be some more changes in our old infrastructure, I’ll notify when anything noticeable happens.