fixed default retention suggestion

the previous settings creates an aggregation problem because of http://graphite.readthedocs.org/en/0.9.10/whisper.html#archives-retention-and-precision

each metric bucket size needs to divide evenly into the next resolution up.  the first bucket (10s:6h) is 2160 elements, so either 1min:6d needs to be the next bucket, and 10min:1800d the following, or the first bucket needs to be changed to 10s:252m.
The upper_XX metrics also should be aggregated usimg `max` method
Aggregation rule refactoring: to have a single one for upper and upper_XX
Include how many members are in the percentile threshold.
Add tests to verify percentile counts.
Add "sum of squares" to the pre-calculated timer metrics.

Sum of squares (along with count and sum) can be used to do rapid
calculation of standard deviation/variance over an arbitrary number
of consecutive intervals [1].

[1]: http://en.wikipedia.org/wiki/Standard_deviation#Rapid_calculation_methods
Persist counts on timers with no values.

This change brings timer `count` and `count_ps` functionality into
parity with the standard counters by causing them to send zeroes when
their timers haven't been seen during the flush interval.

Fixes #370.
Fix status

This init script wasn't working with puppet, but after I changed this line it's working fine. It looks like if it returned the wrong status code, so puppet was always assuming it's runnning even when it's stopped.
lib/helpers: fixed is_valid_packet()

This commit introduces following changes:
 * Be liberal in what you recieve - do not rely on regexps for packet
   parsing but instead accept anything that can be parsed by JavaScript
   as a number e.g: +1e-17, -0511, 0xDEADbeef, etc
 * Accept both positive and negative counters with explicit / implicit
   sign
 * Provides more strict error checking then regexp, for example
   following strings match previously used '([\-\+\d\.]+' regexp:
   .
   .123.
   .\-+\0\+-.1-

Also while here added more tests.

Closes: #350 #357

Signed-off-by: Alexey Ivanov <SaveTheRbtz@GMail.com>
Update URL of Graphite documentation in README.md.
Merge pull request #382 from SaveTheRbtz/helpers

lib/helpers: fixed is_valid_packet()
tests: improved tests for lib/helpers
lib/helpers: added support for null 'ms' metrics.

Pointed out by: jeffyip in #382 [1]

[1] https://github.com/etsy/statsd/pull/382#discussion_r9887857
Julia statsd client implementation
Merge pull request #398 from bass3m/master

Julia statsd client implementation
Adding elasticsearch backend link to docs.
Merge pull request #397 from SaveTheRbtz/helpers

lib/helpers: added support for zero 'ms' metrics
Clarify use of backends with example
Merge pull request #400 from pburkholder/pdb_clarify_backends

Clarify use of backends with example
Merge pull request #379 from pbehrisch/patch-1

Fix status