Add shims for Surprise

[mdekstrand]

[sherif-med]

any ideas for this issue, what are the proposed approaches ?

[mdekstrand]

What needs to happen here is to implement the LensKit algorithm interfaces on top of Surprise, translating the data into the form Surprise expects and translating the results into LensKit's result formats.

The Implicit and HPF modules have examples of other shims. We just need to do a comparable thing for Surprise, and to add tests that exercise the new code.