Add a launch.json option to capture output from stdoutput and stderr streams

[igelbox]

This will help with microsoft/vscode#19750.
We'll just set "outputCapture": "std", in the launch.json file.

...
  "configurations": [{
    "name": "Debug Jasmine",
    "type": "node",
    ...
    "debugCapture": "std",
    ...
  }
...

This approach is more lightweight than the original proposed "console": "internalConsole" approach, which starts a separate shell process with (e.g. on my PC zsh with lots of plugins is started).

[msftclas]

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[roblourens]

This is great, thanks!

When capturing stdout/err, I think it shouldn't show messages that come over the debug port, to avoid showing duplicate messages. Can you override onConsoleAPICalled to disable that in this case?

[igelbox]

@roblourens thanks for your feedback.
I didn't quite get your point. The onConsoleAPICalled is already overridden in this class, so I've just added a conditional return statement there to prevent duplicate messages.

[roblourens]

You are quite right. Sorry, I misread... I will merge this tomorrow.

[roblourens]

Thanks!