Change sights.yml to see.yml
More gracefully handle nonexistent plugins
Change rendering of plugin display_name
Clearly express the conditional nature of running plugins
Move circle require to circle plugin
Change to provide plugins with their config
Clean up error reporting
Use loop do instead of while true

Only the performance benefit of using while true comes to mind here as
an argument against using loop do. I don't think we're worried about
this being the performance bottleneck here(?) so I'm going to go with
loop do as it "seems" more appropriate.

Let me know if you think differently? @mwynholds
Bump to 0.0.18
Clean up plugin execution error output
Refactor away some duplication
Comment on sort_by
Refactor the runner run logic to be more focused
Move ProgressIndictor out of Runner class definition
Clean up run
Factor out config logic
Refactor away Runner class