removed std::cout and std::cin from dump.hpp, added ostream argument to print(), removed default constructor from both dump_reader and dump_writer
removed std::cout from the default arguments of test_gradients within model/util.hpp. common/command.hpp already calls it with streams
removing std::cout and std::cerr from stan/mcmc/*
changed implementation of covariance and correlation to throw exception instead of outputting to std::cerr
Merge branch 'develop' into feature/issue-382-remove-std-cout-cerr
updating mcmc_writer_test.cpp
removing std::cout from print.hpp (leaving it in print.cpp)
removing reference to std::cerr
adding ostream reference to init_adapt
using output_stream instead of std::cout
removing comment containing std::cout
removing std::cout and std::cerr references from src/stan/io/stan_csv_reader.hpp
removing std::cout from code
fixed print.cpp
Merge pull request #654 from stan-dev/feature/issue-382-remove-std-cout-cerr

Fixes #382. Feature/issue 382 remove std cout cerr
Revert "Merge pull request #654 from stan-dev/feature/issue-382-remove-std-cout-cerr"

This reverts commit c9ae1b57ce895f37c2140515b07daa416a7f47f9, reversing
changes made to 79f55b02bc78d05b084e87be5a5299ae96ab2292.
Merge branch 'develop' of https://github.com/stan-dev/stan into feature/issue-567-manual-2.3.0