Automated enum of valid variables and adding to it as we add datasets. That way users (and developers) can easily keep track of what variables are available and implicitly have these selections limited only to variables that have been defined as available.

[Niklewa]

          Might be worth making an enum of valid variables and adding to it as we add datasets. That way users (and developers) can easily keep track of what variables are available and implicitly have these selections limited only to variables that have been defined as available.

Originally posted by @azane in #14 (comment)

[emackev]

Related to #59