Handle lone carriage returns as newline

[dpsutton]

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Substitute newline for single carriage returns

#1677

this doesn't totally solve the issue actually. The issue poster was hoping that "foo\rbar" would right foo, return to the beginning of the same line, and then write bar. However, we were stripping carriage returns with no action. We now act as lein repl does, replacing this lone carriage returns with newlines.

The fundamental issue was that text-based status bars didn't work, and it sounds like we don't have plans to fix this, or at least not at the moment. There are lots of things to consider like markers, how we parse up the bencoded string to know when to move to next line, when to zap over current line, etc, and that would be a much larger change.

[bbatsov]

The changes look good. Mention them in the changelog and we're good to go.

The fundamental issue was that text-based status bars didn't work, and it sounds like we don't have plans to fix this, or at least not at the moment.

Well, I wouldn't mind fixing this, but as you said - it's probably going to require a bit of work.

[dpsutton]

Added to changelog along with categories for bugs/features/fixes on master (unreleased)