Add Support for Single Precision (#487)

* passing tests

* Fix change to Project.toml

* fix up tests and add coverage

* Let's try a little print testing

* fix promotion for aat

* Add heavy diagonal to matrices to ensure we have SPD

* lower uniform scaling a bit.

* fix passing scale arguments.

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Co-authored-by: Viral B. Shah <[email protected]>

Author: rayegun