Doc updates: multiple servers (FAQ), pytest tips (README:dev)#820

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neiljp merged 2 commits intozulip:masterfrom

neiljp:2020-11-03-FAQ-updates

Nov 14, 2020

Commits on Nov 6, 2020

FAQ: Discuss support for multiple Zulip servers.
neiljp
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Commits on Nov 7, 2020

README: Add tips for working with pytest.
neiljp
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