moving value_of out of src/stan/math/special_functions.hpp
moving log_inv_logit out of src/stan/math/special_functions.hpp
moving log1m_inv_logit out of src/stan/math/special_functions.hpp
moving logical_negation out of src/stan/math/special_functions.hpp
moving logical_or out of src/stan/math/special_functions.hpp
moving logical_and out of src/stan/math/special_functions.hpp
moving logical_lt out of src/stan/math/special_functions.hpp
moving logical_lte out of src/stan/math/special_functions.hpp
moving logical_gt out of src/stan/math/special_functions.hpp
moving logical_gte out of src/stan/math/special_functions.hpp
moving as_bool out of src/stan/math/special_functions.hpp
removed unused file
removed unused function simple_var()
removed reference to simple_var from math.hpp