Preliminary work on being able to set version via environmental variable, and adding config_info.hpp.
Finish config_info.hpp and apply to critical tests. Clean up Jamfile by making <test-info>always_show_run_output a project-wide requirement.
Correct what config.hpp to include.
Add BOOST_FILESYSTEM_OPERATIONS_TEST_TEMP macro to work around problem of TGitCache holding filesystem/test open for too long, and thus preventing operations_test from deleting its test files at end-of-job. TODO: experiment to see if running operations_test in a "test/temp" sub-directory, and having a .gitignore entry for it would be a cleaner way to solve the problem.