xo-unit: remove unused file

include/xo/unit/quantity2_old.hpp

@@ -1,47 +0,0 @@
-/** @file quantity.hpp
- *
- *  Author: Roland Conybeare
- **/
-
-#pragma once
-
-#include "bpu_array.hpp"
-
-namespace xo {
-    namespace qty {
-        /** @class quantity
-         *  @brief represent a scalar quantity with attached units.  enforce dimensional consistency.
-         *
-         *  Constexpr implementation, can compute units at compile time
-         **/
-        template <typename Repr = double,
-                  typename Int = std::int64_t,
-                  natural_unit<Int> NaturalUnit>
-        class quantity {
-        public:
-            using repr_type = Repr;
-            using unit_type = natural_unit<int>;
-
-        public:
-            constexpr quantity(Repr scale)
-                : scale_{scale} {}
-
-            constexpr const repr_type & scale() const { return scale_; }
-            constexpr unit_type unit() const { return NaturalUnit; }
-
-            constexpr bool is_dimensionless() const { return s_unit.is_dimensionless(); }
-
-            constexpr quantity unit_qty() { return quantity(1); }
-
-        private:
-            /** @brief unit (established at compile time) for this quantity **/
-            static NaturalUnit s_unit = NaturalUnit;
-
-            /** @brief quantity represents this multiple of unit amount **/
-            Repr scale_ = Repr();
-        };
-    } /*namespace qty*/
-} /*namespace xo*/
-
-
-/** end quantity.hpp **/