variables with dots should return an object/array

[tacman]

Instead of converting variable names like "member.code" to "member_code", we should be returning an array or object. This would allow us to do things like

member.code,member.email,task.code,assignment.code,smoke,drink,coffee
tacman,tac@survos.com,TA92482,A21424,1,2,3

And get back arrays for member, task and assignment (as well as the root-level variable).

This can then be incorporated into the various import routines for Survos, like assignment import.