Fix dynamic eval vars in output/repl window

[PEZ]

What has Changed?

• Check if the the current ns of the repl is different from what the form to be evaluated should be using before evaluating (in-ns ...).
• Add pre-eval (conditional) to the commands for setting the output window ns and copying over forms to the repl window.

Fixes #724

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Ping @PEZ, @kstehn, @cfehse, @bpringe