Merge branch 'develop' into cuda
# Fixed Conflicts:
# include/boost/math/distributions/detail/common_error_handling.hpp
# include/boost/math/special_functions/detail/bessel_i0.hpp
# include/boost/math/special_functions/detail/bessel_i1.hpp
# include/boost/math/special_functions/detail/unchecked_factorial.hpp
# include/boost/math/special_functions/next.hpp
