Adds in automatic covariance computation on writes (#454)

* Adds in automatic covariance computation on writes

* Gets covar working

* Fixes geom error

* Tests and modularizes to_isis on the NCG

* Missed new files

* Removes a local commit accidentally merged in

* last manual rollback

* Removed pd debugging statement

* Removes typo

* Removes typo

* Fixes db port

* Fixes db port

* Fixes none in radius for covar

* refactors covar computation out of to_isis

* Adds doc strings

* Adds docs for the new controlnetwork file in the io moduke

* Reverts port change