No events raised with UseEvents flag on dotnet 3.5

[Mystfit]

I've converted NetMQ.Zyre to project.json and added net35 as a framework target. When initialising a new Zyre object with the UseEvents flag, events will be processed internally for all the usual messages (hello, enter, join etc) but these events don't bubble up to the api level.

For example, zyreObj.EnterEvent += SomeFunction will never be called when the Zyre object receives an enter event, even if the logger reports that an ENTER was received.

If I turn off UseEvents, hook up the internal mailbox to my own NetMQPoller instance and handle all the API messages myself, I can receive all of the usual Zyre messages. However, I run into another issue, where Zyre will break my existing NetMQPoller from receiving any messages from normal NetMQ subscribers, depending on when the poller and Zyre were both started. This is a different issue that I hope I can fix by letting Zyre use it's own internal NetMQPoller by setting UseEvents to true.