Breaking Change in Persistent Subscriptions Client API

I finally bit the bullet and made the change I have been debating for
about two months. I think the small breaking change now is worth
saving the confusion later.

The connecttopersistentsubscription method was odd. Its arguments were
GroupName/StreamName while everything else took StreamName/GroupName.

This is a breaking change if you are using the pre-release version of
PersistentSubscriptions (though a minor one).

Feel free to comment on the PR here