Parsing dos line ending delimited line protocol is still illegal in most
cases.

closes #2178

* Make Logparser Plugin Check For New Files

Check in the Gather metric to see if any new files matching the glob
have appeared. If so, start tailing them from the beginning.

* changelog update for #2141

in this commit:

- centralize logging output handler.
- set global Info/Debug/Error log levels based on config file or flags.
- remove per-plugin debug arg handling.
- add a I!, D!, or E! to every log message.
- add configuration option to specify where to send logs.

closes #1786

this log format is likely soon going to be removed from a future
influxdb release, so we should not be recommending that users base any
of their log parsing infra on this.

closes #1436

This also fixes the bad behavior of waiting until runtime to return log
parsing pattern compile errors when a pattern was simply unfound.

closes #1418

Also protect against user error when the telegraf user does not have
permission to open the provided file. We will now error and exit in this
case, rather than silently waiting to get permission to open it.

closes #1434

closes #102
closes #328