Add comparison to xonsh

[jgarte]

This is a request to add a comparison table or general comparison piece to xonsh.

If you like the idea, should this go in the README?

WDYT

[tusharsadhwani]

Sure, do you want to submit the change?

[jgarte]

I could once I do the research on that.

I don't know zxpy well enough yet. I'd also have to refresh my memory on all of xonsh's features and scope.