Changed the UI from combinations of radio buttons and check boxes to use
just checkboxes. Also changed how the partitions of `use var` space was
logically represented. We now present 3 options - use var on intrinsic
types, use var where apparent, use var in rest of the places. If all 3
are checked, we universally use var everywhere. If only one or a
combination less than 3 are selected, we use var only in those places.
An unchecked option means, user prefers explicit typing for that
scenario.

Not yet implemented : enforcement levels of the fix, fancy previews that
show results for a combination of choices, integrating the options into
code generation service.