Merge #107: example: Remove manual client adding

3499810 example: Remove manual client adding (TheCharlatan)

Pull request description:

  Opening this more as a question, than a change request, because I am not sure what is going on here, since removing it does not seem to change anything in the program's functionality.

  This is probably needed, but it is not clear from the example, or the documentation for what. If it is indeed needed, could the documentation be improved a bit, a comment added to the example or could it alternatively be moved into the `EventLoop` constructor instead? From my understanding `addClient` is eventually called internally when a new connection or proxy is created.

ACKs for top commit:
  ryanofsky:
    Code review ACK 3499810. This code change makes sense, and it definitely doesn't make sense to have an `addClient` call without a corresponding `removeClient` call here.

Tree-SHA512: 0072d429f6029ebd02f34d57996ae3fed94061d0fea3ebf057955632436f179c2cb88b4f4d54bac88b65c1d99060acb902b2ea514f7a88a14f5f7750c0672ea8

Author: ryanofsky

example/example.cpp

@@ -39,10 +39,6 @@ int main(int argc, char** argv)
     std::promise<mp::EventLoop*> promise;
     std::thread loop_thread([&] {
         mp::EventLoop loop("mpexample", LogPrint);
-        {
-            std::unique_lock<std::mutex> lock(loop.m_mutex);
-            loop.addClient(lock);
-        }
         promise.set_value(&loop);
         loop.loop();
     });