Set up tests for TypeMatchingCompletor
Should not return completions when adding text there would cause compilation to fail
Should not produce any completions if the underlying completor produces none
Add TypeAddingCompletor
One result with a successful type should return that
Should work for multiple results
Make rest of app use new completor
Creat OutputCompletor
One result. 100 tests woo!
Many results
Hook up OutputCompletor to the rest of the app
Exploratory work around TypeMatchingCompletor
Add is_supertype_of method
Make sure is_supertype_of returns the right stuff
Add TypeHoleInfoExtractor
Make sure load_haskell_file is called
Add StringAcceptingGhci
Implement StringAcceptingGhci
Add back load_haskell_file
Refactor out testing failure