Review and standardize error handling

[1dustindavis]

A lot of functions handle errors in different ways. Some handle them within the function, some return to the calling function, others don't do anything with them.

Now that logging is handled consistently with a panic called via gorillalog.Error(). We should implement defer and recover in places where it makes sense (the installer, status, and download pkgs come to mind).

[gyamada619]

Partially addressed in #38 that @YourCrush and I worked on today. Will continue adding defer and recover logic where I locate mention of gorillalog.Error(), assuming that the program will panic and terminate unless recover is implemented.