Feature/issue 667 fma calls fma

#### Summary:

Uses std::fma to resolve base arithmetic in fma function

#### Intended Effect:

See summary.  Resolves issue #667.

#### How to Verify:

You can look at the implementations.  The tests don't change because behavior doesn't change.

#### Side Effects:

None.

#### Documentation:

Already documented.

#### Reviewer Suggestions:

Anyone.