Many of the examples provided within documentation are using a single
dash for the command line arguments, but the telegraf executable
explicitly has two dashes.

There are also some inconsistencies with the ordering of the command
line argument examples.  I've ordered them so that the examples will
show: config, config-directory, input-filter, test

closes #1439
closes #1440
closes #1441
closes #1442
closes #1443
closes #1444
closes #1445

* Adds support for Tengine

* Added #1390 Tengine PR to changelog

closes #950

This will basically make the root directory a place for storing the
major telegraf interfaces, which will make telegraf's godoc looks quite
a bit nicer. And make it easier for contributors to lookup the few data
types that they actually care about.

closes #564