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/box_example.cpp

@@ -11,7 +11,6 @@
 
 using namespace units::experimental;
 
-
 struct Box {
 
   static constexpr auto air_density = density::kg_per_m3<>{1.225};