* Customizable 'separator' option instead of hard-coded '_'
* String values are sent as "State" instead of "Metric", preventing
Riemann from rejecting them
* Riemann service name is set to an (ugly) combination of input name &
(sorted) tags' values...this allows connecting different events for
the same input together on the Riemann side
closes#642
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