Added a wrapper for t-SNE method implemented in tapkee library and a basic unit test for it.

Added a wrapper (CTDistributedStochasticNeighborEmbedding class) for t-SNE dimensionality reduction method, implemented in tapkee (according to https://github.com/shogun-toolbox/shogun/issues/946).

Also added a basic unit test for it, that embeds the test data from 3D to 2D using implemented wrapper, and checks that resulting data is actually in 2D, and that number of features stay the same.