The ess company sources should be grouped, when they are not grouped
they are pretty buggy (like not showing completions under certain
circumstances).
To see the problem, try opening an R file and start the interpreter.
When you type the following ([] is the cursor):
setN[]
You will see completions offering up `setNames`. Press `<enter>`.
Now, try doing the following:
setNames(setN[])
You will see no completions. Company is trying the `company-R-args`
source, failing it, then skipping the execution of the
`company-R-objects` source.
Grouping them together fixes this, and is what's done within ess itself.
