* Move non-templated constructor implementation to the source file

* Optimize constant constructor for uniform constant

* Cleanup

* Much faster deserialize constant

* Adding unit tests

* Unit tests

* Update unit test

* Cleanup

* style

* Cleanup nbench output

* wip

* Fix specializations

* Change from unique to shared_ptr internally

* Enable copy of Constant

* cleanup Constant ctors

* Fix copy contructor

* Fix compile error
Co-authored-by: Scott Cyphers <diyessi@users.noreply.github.com>