Clean up the Foldable module, deprecate the *Safe variants
Rewrite Foldable in terms of a common abstraction
Remove some redundant copies of duplicate signatures
Add Foldable minimum functions
Add a module of Exact functions
Refactor the main Safe module
Tweak the error messages in Safe.Foldable
A couple of new utilities
Enable the Exact code
Improve the README
Add a .ghci file