Make EVERY2 an alias for the LIST_REL constant.

Preserve the EVERY2 theorems, at least for the moment.

This issue was first identified in discussion around github issue #98
Make quotient_option$OPTION_REL an alias for option$OPTREL.

Preserve quotient_optionTheory.OPTTION_REL_def as a theorem derived
from OPTREL’s definition.

This is another issue arising from discussion associated with github
issue #98.