[Don't merge] demonstrate #1187

[0x53A]

This demonstrates #1187:

If $ErrorActionPreference = "Stop" was set, powershell converts any sub-process writing to STDERR into an exception.

When the output of FAKE is redirected (either file-redirection, or just running it in ISE), it writes an empty string to STDERR after it successfully finishes.
The exit code of FAKE is 0.

My guess is that it flushes some kind of buffer before exiting.

I did a manual binary search with the package versions, and it looks like 4.14.5 is the last GOOD version, 4.14.7 is the first BAD version.

I will try to find the exact commit next week...

[forki]

What about this now?

[0x53A]

This script runner was just quickly thrown together.
I will try to create a unit test which checks that a successful build script does not write to stderr.