Make DO_OR_GOTO_ERR macro look like a function
Add JSON plugin for CGP

The next release of CGP (current master branch) will only support JSON
plugins.
Merge pull request #1 from fishilico/upstreamable

Thanks for the fixes (I'll backport this into the other pull request ;)
Remove wrong ds_names (from nut)
Enhance CGP plugins with more details
Ignore SMI graph if CGP support this type
Rename instance type "pc%02d" to "pkg%02d"