Give up on `xbuild /t:run` for now.

Running an interactive command line tool within xbuild/msbuild doesn't work well.

On Windows, we can use `start /wait`.

On XWindows we can use `xterm -e`.

I don't know what works on Mac.

I don't know what works in SSH or at Linux text terminal.

For now, let people run it themselves. Not that hard.
Merge branch 'build-steps' of https://github.com/JayBazuzi/Pash2 into build-steps