Consider changing the argument order for HazardCalc command line usage

[emartinez-usgs]

Consider changing the argument order for HazardCalc command line usage so custom sites are specified before custom configuration. It seems more likely to have a custom set of sites of interest rather than custom configuration for the default site.

[pmpowers-usgs]

Move all site and map specification out of config. Sites will always will always be processed by supplying a file (geojson or csv) as first argument, followed by custom calc configuration. Also should consider single site, see #93.

[pmpowers-usgs]

All site spec has been removed from config. User must specify site(s), see new Sites wiki entry. This may be followed by an optional overriding calc config.