- Fixed SQL compiler's awareness of top-level column labels as used

- Fixed SQL compiler's awareness of top-level column labels as used
  in result-set processing; nested selects which contain the same column
  names don't affect the result or conflict with result-column metadata.

- query.get() and related functions (like many-to-one lazyloading)
  use compile-time-aliased bind parameter names, to prevent
  name conflicts with bind parameters that already exist in the
  mapped selectable.