This uses a *slightly* patched version of node's uri module to allow
commas and colons in hostnames, which causes the parsed representation
of replica sets to be less-awful.
Hostname are still somewhat broken in this representation, because we
have an array of hosts expressed as a list, but this is the
minimum-effort solution to getting format to be able to reprint a parsed
replica set correctly.
I understand that we probably don't want to merge this (for a lot of
reasons), but at least this shows exactly where the issue is, and yields
some useful discussion.
836582fdb1