PersistentTaskController logging health monitoring logs under "System.String"

[smerrell]

Since logging with just _logger.Info(() => ... here our logs are getting cluttered with messages like:

2015-02-09 18:57:50.1063  INFO System.String - Finished running task health monitoring on node FubuTransportationApp@SMERRELL02

I should have a Pull Request for this at some point, just wanted to make a note. Also, these messages can be filtered with this NLog filter

<logger name="System.*" minlevel="Debug" writeTo="<nlog target here>" final="true">
  <filters>
    <when condition="starts-with('${message}', 'Finished running task health monitoring')" action="Ignore" />
  </filters>
</logger>

[jeremydmiller]

@smerrell @RyanHauert & I were talking about this this morning. I think our vote is that we'll completely eliminate ILogger.***(string) methods such that ILogger is only usable for semantic logging kinds of things and adjust fubu internal code accordingly.