v0.3.2 addition of alpha-dpp sampler
New version following #62
@danielecc contributed with an implementation of a fast exact Finite DPP sampling algorithm which does not require looking at all items and applies to both DPPs and k-DPPs.
Sampling from a k-DPP without looking at all items
Daniele Calandriello, Michal Derezinski, Michal Valko, NeurIPS, 2020.