Peter M. Groen / FlashMQ

We use epoll now to change readiness.

The test cases give a bunch of warnings, but that's the COMPARE macro's
fault. Let's see what to do...

The MQTT docs showed a wrong condition for checking malformed packets.

And, we have to grow buffers to MAX_PACKET_SIZE, otherwise we can't
process. I still have some inteligent buffer shrink logic in mind.

There still is a bug: writing a very big packet. I wrote the test case
already.

Because the connectionClose would set fd=-1, clients were never properly
removed from the map, because the fd is the key.

Also fixed a locking issue when an exception happened.

Also materializes some concepts about MqttPacket.

I put the main app in a seperate class for it, because it was easier.