Significant config and output updates

Created by: pmpowers-usgs

This pull request and prior commits address a number of issues, including:

• Saving a copy of the log and config to the results directory
• Major restructuring of CalcConfig (and it's JSON representation) into groups of related settings/parameters.
• Adding a variety of configuration options related to output and performance. One can now:
  • Specify an output directory. If the directory already exists, results are never overwritten in favor of incrementing the output directory with an appended integer.
  • Output Poisson probabilities.
  • Control the number of system source ruptures that get processed together.
  • Control the size of thread pools.
  • Control when to flush results to file(s)
  • Be more specific about the types of hazard curves to save.

Resolves #56 (closed) Resolves #66 (closed) Resolves #99 (closed) Resolves #100 (closed)

etc/examples/1-hazard-curve/README.md

@@ -15,6 +15,8 @@ The result of this calculation should be available as a single comma-delimited f
 
 Note that not all [calculation configuration](https://github.com/usgs/nshmp-haz/wiki/Configuration) parameters need be supplied; see the [configuration file](../../peer/models/Set1-Case1/config.json) for this example model.
 
-Also note that all output is written to the current working directory. In the next example, we'll override the model supplied configuration with a custom file.
+Also note that all output is written to a `curves` directory by default, but the ouput destination can be specified via the [`outputDir`](https://github.com/usgs/nshmp-haz/wiki/Configuration) parameter. In addition to hazard curves, the calculation configuration and a log of the calculation are also saved.
+
+In the next example, we'll override the model supplied configuration with a custom file.
 
 #### Next: [Example 2 – A custom configuration](../2-custom-config)