adding cwd param to terminal api endpoint

[qntnrbns]

I am trying to fix this issue jupyterlab/jupyterlab#1366 in jupyterlab so that terminals open in the current working directory.

I am bumping the version of terminado to 0.8.3 to capture jupyter/terminado#70, and adding a json param to the terminal creation endpoint.

I want to write a test for this, but could use some guidance w.r.t. the new test suite and how much we need to mock the creation of the terminal

[Zsailer]

Thanks, @qntnrbns! Let a few comments inline.

[Zsailer]

Great work writing the tests @qntnrbns! Thanks for working on that.

I'm not sure why the Windows tests are hanging. I'll try to look into this later today.

Before that, I'm putting together a minor release (0.2.0) today—if your PR doesn't get in for that... we'll put a patch release out right after with this PR 🎉

[qntnrbns]

@Zsailer were you able to fix the windows build?

[Zsailer]

@qntnrbns We likely need to make these tests conditional on the running platform. The same terminal params that work on Linux/MacOS won't work on Windows.

There are two options for this PR:

1. We just skip these tests on Windows.
2. Or we write tests with separate terminal parameters for each platform.

I'm fine with either choice at this point.

Note that we've ripped out the conftest.py file and make it a pytest_plugin. Would you like to try updating your PR? Or I'm happy to move this forward if you're limited on time.

[qntnrbns]

I took a shot at it, but I don't have a windows machine

[blink1073]

Given that terminado itself skips all but the basic tests on Windows due to timeouts, I think it is fair to just verify that we can submit the kwargs on Windows and not wait for a response.

[Zsailer]

Closing in favor of #201 (I was having issues pushing changes directly to this branch).

Thanks for this feature, @qntnrbns!