failing spec for issue 7
fixes: do not subscribe more than once [issue #7]
failing spec for subscription happing when connections of different topics already exist
failing specs to test `subscribed?` is topic sensitive
ensure `subscribed?` and `subscribers_of?` are topic sensitive [#7] [#8]
reword spec descriptions
Merge pull request #9 from krisleech/issue_7

Fixes issues #7 and #8