Clean up options holder class (#6458)

Clean up options holder class (#6458)

This PR does some cleanup on the options class: it puts the option defaults into the member declaration and removes the explicit constructor; it puts the holder into a unique_ptr; it uses the regular struct copy operation instead of reconstructing the holder object; it moves some macros required for option defaults into the option holder header.
Also, this PR removes some obsolete code related to suggestions for typos.