Performance inefficiencies in CChaiGraphics

[Samir Menon]

Since chai depracated Eigen compatibility, our wrapper requires a lot of copies. Perhaps there is a more efficient way to do this.

[Kenji Hata]

The quat --> rotation matrix could be manually calculated instead of using the Eigen functions.

[Kenji Hata]

Re-enable Eigen compatibility in Chai instead and test to see if it works

[Samir Menon]

Duplicate of #75.