v46

• Experimental support for coroutines. Use CO_RETURN (or LR_CO_RETURN)
  for a member function that has a coroutine return type. Use CO_THROW
  (or LR_CO_THROW) to throw from a coroutine. Use as many CO_YIELD
  (or LR_CO_YIELD) from a coroutine function as you like, as long as the
  promise type supports it.

  The experimental support must be explicitly enabled with

    #define TROMPELOEIL_EXPERIMENTAL_COROUTINES
    #include <trompeloeil.hpp>

  trompeloeil::stream_tracer does not produce correct result for coroutines

• Corrected output of input-range like types. Thank you @DNKpp for
  the fix.

• The self test program "custom_recursive_mutex" now says that it's
  succeeded. Thank you @yurivict for reporting the confusion.

• Self test programs are only build when explicitly setting
  -DTROMPELOEIL_BUILD_TESTS=yes to the CMake command line.

• The self test programs require a higher version of CMake (3.19 currently)