This will make 'alloy_build' shorter

This merge will add 'tail' feature to the attach_mail_file function and cut down 'alloy_build.log' to 100 lines in case there were no errors and 400 lines otherwise. It will also most likely fix the bug when no 'run_tests.log' was being sent in case of build failure. Yet no 'stability.log' will be sent in case of build failure.