Add software-properties-common to dependency script

[FuRy2K]

Need to add a check for software-properties-common in the dependency script.

I started a fresh GCE instance, and this was not included on their install and caused errors adding apt repositories.

[desimaniac]

If i create a new one, would you be able to test it on another fresh gce instance ?

[desimaniac]

I added it in now.