Set encoding on v0.3.0

[mcollina]

This is #111 ported on top of the new parser.

It is a fast fix for #109.

@adamvr for backward compatibility I have put a default on the Connection object to decode stuff as utf8.

I still need to run some benches to check if that call() is a problem.

[mcollina]

Right now the syntax for not encoding is setEnconding(null), which I do not like.

I'll say we can move it to setEncoding('binary').

[adamvr]

👍 setEncoding(null) was super ugly.