Pickle support

[bodgit]

Unsure if this would provide a performance benefit or not, some investigation required.

[davewongillies]

From #graphite on freenode:

10:00 AM <davewongillies> drawks: what sort of difference do you see when you send using pickle? 
10:07 AM <drawks> well pickle is phenomenally faster
10:08 AM <drawks> for string protocol you are basically doing strings to split and then you are doing input validation and type conversion for every datapoint
10:08 AM <drawks> whereas with pickle you get a glob of like 500 datapoints and you do a single deserialization and then you are off to the races
10:08 AM <drawks> you jump past large bits of slow looping code

So I'd say from a graphite-amqp-tools point of view, it might not make a difference but it seems like for the carbon-cache/carbon-relay, it does.