examples, alternative namespaces : Part2 of put alternative namespace definitions in local headers.

examples, clcpp_response,alternative_namespaces::clcpp_response : use fmt functions for showing precision of quantities
examples, alternative namespaces : combined the alternative namespace quantity typedefs in header files.
examples, alternative namespaces : add simple timer example

example/alternative_namespaces/units_str.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <units/physical/dimensions.h>
+#include <units/physical/si/prefixes.h>
+#include <units/quantity.h>
+// get at the units text of the quantity, without its numeric value
+inline auto constexpr units_str(const units::Quantity AUTO& q)
+{
+  typedef std::remove_cvref_t<decltype(q)> qtype;
+  return units::detail::unit_text<typename qtype::dimension, typename qtype::unit>();
+}