Outputs install logs to stdout.

I fixed #362. Now we can output install logs(generated by `TestTask`, `ConfigureTask`, `InstallTask`, and `BuildTask`) to stdout using `tee` command.

* add --stdout option to InstallCommand.
* use tee command in CommandBuilder when --stdout is given.
I think this PR works, issue #362 is to let you record the output in the log file and also output the text in the console.