struct & const fixes

[brandonbloom]

I was getting some output that looked like

const Foo = *Bar{
  Baz: 1,
}

The first commit fixes const to var and the second commit removes the *. Resulting in the correct output:

var Foo = Bar{
  Baz: 1,
}

The second commit seems to have some cascading impact to struct fields, fixing cases where there were double-optionals, like pointers to slices.