Ability to disable preEval and refer to mutliple eneity fields in 'columnDef.field'

I want to have fields like someProp || 'N/A', but the current preEval function turns it into something like row['eneity']['someProp || \'N/A\''], which is obviously broken.

In addition, if I want to refer to more than one property in the expression, I'll have to manually prefix row.entity., which is also not guaranteed to work.

Can a switch be added to allow "raw" expressions in field without preEval and the prefixing of row.entity. It might be necessary to provide a local variable to the expression (e.g. entity) which points to row.entity.