Added append parameter to graphite sink
Refactored graphite sink line parsing

I added a hostname parameter to match our existing statsd namespacing.
The list comprehensions also started to get a little unwieldy, so I
moved everything out to a generator function.
Added 90th percentile to the list of percentiles

We use the 90th percentile a bunch, so I've added this in.

It'd be great if this was parameterized, but this is a hack that'll
work for us.
Changed metric names to match statsd

Upper_* == p*.

This metric grabs the value at the nth percentile of the sorted
array of timer values for each flush interval. I've just renamed them.
Merge pull request #1 from jefffm/master

Merge in upstream + jefffm/statsite