Add the Result Crock

[evilsoft]

Getting results (?)

This PR adds the new Result crock as requested by this issue#6.

This is just like the Either type, except you can accumulate Errs using ap. Its constructors are Ok and Err.

Also adds all the required transforms for this new type:

• eitherToResult
• maybeToResult
• resultToAsync
• resultToEither
• resultToMaybe

Also it turns out that arrayToList and listToArray were not exposed to the public API. This exposes those as well.

[coveralls]

Coverage remained the same at 100.0% when pulling 2200e72 on add-result into 26b1e71 on master.

[evilsoft]