CoR improvements

About

This MR fixes a couple of bugs and brings simplifications in the codebase.

To do

• Create a CORDispatcher class for pipeline. It takes dataset_info (and other pipeline-related params) and dispatches to the suitable estimators.
• Simplify estimators to act on simpler data structures
• Fix #368 (closed)
• (Bonus) Save CoR result
• End-to-end reconstruction test