Memoize fibonacci

[milesfrain]

Fixes #182

[JordanMartinez]

If I'm understanding you correctly, adjusting fibMemo in the above 3 ways will remove the performance benefit of memoization.
Could we convert those examples to code, add them as statements to main but leave those statements commented out with a header above explaining why?
For example:

main :: Effect Unit
main = do
  log $ i "basic fib result" $ fib 7
  ...
  log $ i "fibSlow result: " $ fibSlow 7

  -- These examples type check and seem
  -- to incur the performance benefits of memoization. 
  -- However, they do not. Uncomment them to see for yourself.
  -- log $ i "fibBroken1 result: " $ fibBroken1 7
  -- ..

I think I'd also prefer that main be immediately below the import statements, so that one can see what will run and then see how they are defined.

Thoughts?

[JordanMartinez]

ping @milesfrain

[milesfrain]

Yeah. These are good suggestions. I'll circle back to this task in about a week. Trying to wrap-up the try-purescript enhancements first.

[JordanMartinez]

In that case, I'll push changes to this PR and merge. If you have feedback on what I've done, feel free to open an issue.

Stay focused on the try-purescript stuff as that's more important.