aesthetics
extract temporary_directory.tcc
extract pushd_temporary_directory.tcc
prohibit conversion, it makes no sense
temporary_file
we shouldn't return a const&
fix compile error
temporary_file: eliminate a copy
temporary_file: allow file outside tempdir
temporary_file: boost path conversion
temporary_file: delegate construction
temporary_file: rm std::cerr logging

i should of another way to learn about an issue at destruction. but
doing nothing is better than writing to std::cerr, because i'm not sure
there is always someone to pay attention to std::cerr.
temporary_directory: eliminate a copy
temporary_directory: boost path conversion
temporary_directory: rm std::cerr logging
pushd_temporary_directory: eliminate a copy
pushd_temporary_directory: boost path conversion
pushd_temporary_directory: rm std::cerr logging
temporary_file: operator<<, operator>>
temporary_file move semantics