Need example for one-class matrix factorization

[wschin]

Currently we only have one test as our example. We should add one into our sample project. Also, in that actual example, we need to tell user to install MatrixFactorization nuget. The ultimate scope of the new example is to cover everything user needs to do to run one-class matrix factorization.

Also, because of some settings in our test framework, our tests are not examples which can be run by copy-and-paste.