* lessEqOp    -> lessEqualOp
  * greaterEqOp -> greaterEqualOp

  to avoid ambiguitity with other forms such as 'plusEqOp' where the
  'Eq' implies an assigment. The name change also aligns better with
  C++ <functional> names such as std::less_equal, std::greater_equal

ENH: simple labelRange predicates gt0/ge0/lt0/le0

- mirrors scalarRange tests.
  Lower overhead than using labelMinMax::ge(0) etc since it does not
  create an intermediate (is stateless) and can be used as a constexpr