New parser & performance

Increased performance over more than 10%. 
master performance on my machine is around ~14k msg/s with a broker, bomber and one subscribe.
This branch performance is around ~16k msg/s on the same setup.

It does that by using two main features:
1) use of binary payload (turned off by default) - it's up to the user decoding the payload.
2) creating less JS objects (mainly arrays).
3) a little bit of inlining.