Allow certificate input via any object that responds to read

[kyledrake]

With our implementation, we pass certificates via a call to a remote database. So we don't keep them as files locally, so the File.read approach doesn't work for us without trickery (such as using Tempfile#path).

This allows developers to provide an IO object that responds to #read as well. It's not perfect (a better solution would be to allow the PEM to be passed directly somehow) but it should work for most people I think!

Tests are passing. Let me know if the upstream merge screwed up the pull and I'll re-apply the code without the merge.

[vanstee]

Looks good to me. Thoughts @alindeman @stevenharman ?

@kyledrake Do you mind rebasing out that merge bubble?

[alindeman]

Cool idea! +1 to merge minus the bubble.

[kyledrake]

I've never attempted to do a rebase, but I will make an attempt right now.

[vanstee]

Something like this should do the trick:

git checkout certificate_string_io
git reset --hard 97ea06b
git pull --rebase upstream master

[kyledrake]

Alright, the merge is gone. I think this guy is ready to go!