Work with Result

[cameroncros]

This library would be very useful if it worked with Result return types, and I have hacked up a proof of concept:

cameroncros@cc9af51

Im envisaging adding a #[memoize::memoize_result] that would do more or less what I did in that commit.

Is this worth working on? Are you interested in it?

[cameroncros]

I've put up an MR: #43