Explicity disallow get_idx for boolean type, to avoid ambiguity with a map.
Explicity disallow get_idx for boolean type, to avoid ambiguity with a map.

bassosimone/yaml-cpp,steinwurf/yaml-cpp,bassosimone/yaml-cpp,steinwurf/yaml-cpp,bassosimone/yaml-cpp,bassosimone/yaml-cpp,steinwurf/yaml-cpp,steinwurf/yaml-cpp