* [WIP] Add BCUT 2D descriptors
* Use the standard RDKit license
* Add Check for EIGEN3
* Add vector param, fix some formatting, remove debug print
* Add make_burden function, optimize symmetric eigenvalues
* Add some tests, finalize API
* Make the python API return tuples
* Updates docs
* Remove unused variable
* Fixed up C++ tests
* Remove std::pair wrapper, don't build BCUT when missing EIGEN
* Add bigger test case for BCUTs
* Accidentally removed the wrong code
