update R2.1 variable example to have an extended SO variable
add variable as a boolean on data criteria since we can have a satisfies all/any variable... that means we cannot use definition.
fix test related to variable attribute not getting set
add additional timing relationships to HQMF model types
Cloning of variables with handling of occurrences
move fixing variables to the R2 document rather than the model document
Merge branch 'update_variable_example', fixes #166