fixes #1636 
fixes #2315 

closes #2519

Report count of processes in dead (X) process state from the processes input.  This process state is only valid on Linux.

closes #2513

Add information about default configuration file locations.  Also mention that the config directory option is available.

* Add configuration docs to Postgresql input plugin

Add configuration docs to PostgreSQL input plugin README (mostly from the source code) though I've not included the configuration example that seems to use all he connections on the database[1].

[1] https://github.com/influxdata/telegraf/issues/2410

* Fix typo in readme and sampleConfig string.

closes #2448

* Exporting Ipmi.Path to be set by config.

Currently "path" is not exported, giving this error when users try to
override the variable via telegraf.conf as per the sample config:

`field corresponding to `path' is not defined in `*ipmi_sensor.Ipmi'`

Exporting the variable solves the problem.

* Updating changelog.

added PDH_FMT_NOCAP100 format option

closes #2483

hopefully this will fix #2472

During issue #2215 it was highlighted that the current behavior where
rules without a comment are ignored is confusing for several users.

This commit improves the documentation and adds a NOTE to the sample
config to clarify the behavior for new users.

Tweak formatting of `LogicalDisk` counter array to have one entry per
line.

closes #1433

closes #2466

closes #2178

closes #2071

closes #2414

fixes #2380

closes #2390
closes #2404

fixes #2282

The docker engine-api package we use needs golang 1.7+, see:
https://github.com/docker/engine-api/pull/382#issuecomment-244512952

So telegraf won't compile without 1.7