add aggregator config option to turn off logging of unmatched metrics

this commit adds a config option which can be added for the aggregator
instances to avoid noisy logging of unmatched metrics in console.log,
introduced in 4424e46.
Chown created subdirs if USER specified

In a setup with:

LOG_DIR = /var/log/carbon and the
USER    = carbon

If the --instance parameter is supplied to multiple instances of each daemon,
the daemon will create subdirectories of LOG_DIR like carbon-cache-a,
carbon-aggregator-b, etc. However, these subdirectories are owned by the
user starting the daemon, not by the USER= specified in the config file.
Only the console.log will be created, because all the other log files
are created after the daemon switches USERs.

This change makes the daemon chown() the newly-create directories to the
configured user if one is configured. To keep this simple, it now creates
only one level of directory, so you can no longer set
LOG_DIR=/path/does/not/exist and have that entire hierarchy get created.

This is related to graphite-project/carbon#149, as it a typical cause of
failing to open these log files.
Merge pull request #150 from jamesjuran/chown_log_subdirs

Chown created subdirs if USER specified
Added Configurable files for aggregation and rewrite rules
Updated example config to demonstrate new options

Conflicts:
	conf/carbon.conf.example
	lib/carbon/conf.py
Fixed really really broken attempt at cherrypicking
Missed a line in last stupidity reversion
Merge pull request #161 from drawks/master

Cherry picked 1928191 from 0.9.x into master - Adds configurable rewrite, relay, aggregation rule files
fixed a typo, "-"!="_"
remove daemonize for compatability with twisted 13.2.0
Merge pull request #184 from ImmobilienScout24/twisted_13.2.0_compat

remove daemonize for compatability with twisted 13.2.0
Demonstrate that hash positions can collide
Remove test running since trial handles this
Prevent hash ring positional collisions
Merge pull request #196 from jssjr/hashing-bug

Hash ring collisions in sufficiently large clusters
do not log OSError from os.makedirs, when the dir already exists
check against errno.EEXIST
carbon.conf comment clarification

MAX_CACHE_SIZE unit was not clear.
Merge pull request #206 from ImmobilienScout24/fixed_mkdir_logging

do not log OSError from os.makedirs, when the dir already exists
Add filter against metrics with misplaced dots in blacklist example

This helps preventing issue #181
Merge pull request #230 from g76r/f_doubledots

Add filter against metrics with misplaced dots in blacklist example