Ia/matrix projections lsi

[immanuelazn]

Details

This PR allows for projection into LSI spaces, as planned with an sklearn-esque interface. We port over both variable feature selection, and LSI. fit(), project() and short_description() methods have been created for both these steps.

Currently the implementations utilize a lot of the previously created LSI implmementation. I am refraining from moving that over until review is concluded. However, this PR already contains some initial tests, and a demonstration that we can concat two PipelineSteps together, to fit and project.

Tests

• Tests were created to make sure initialization, as well as fit() and project() methods work for variable feature selection and LSI.
• Tests were also created to make sure pipelines can be created between these two individual steps, with fit() and project() working from the Pipeline implementations of these two methods