optional.get to orElseThrow

src/main/java/gov/usgs/earthquake/nshmp/calc/CalcConfig.java

...ain/java/gov/usgs/earthquake/nshmp/calc/HazardExport.java

src/main/java/gov/usgs/earthquake/nshmp/calc/Site.java

src/main/java/gov/usgs/earthquake/nshmp/calc/Sites.java

...in/java/gov/usgs/earthquake/nshmp/data/DelimitedData.java

...ava/gov/usgs/earthquake/nshmp/data/MutableXySequence.java

...n/java/gov/usgs/earthquake/nshmp/geo/json/Properties.java

src/main/java/gov/usgs/earthquake/nshmp/gmm/GmmInput.java

...in/java/gov/usgs/earthquake/nshmp/gmm/UsgsPgvSupport.java

.../java/gov/usgs/earthquake/nshmp/internal/www/WsUtils.java

...java/gov/usgs/earthquake/nshmp/model/FaultRuptureSet.java

src/main/java/gov/usgs/earthquake/nshmp/model/GmmSet.java

src/main/java/gov/usgs/earthquake/nshmp/model/MfdConfig.java

...ain/java/gov/usgs/earthquake/nshmp/model/ModelLoader.java

...n/java/gov/usgs/earthquake/nshmp/model/SourceFeature.java

.../java/gov/usgs/earthquake/nshmp/model/ZoneRuptureSet.java

...ov/usgs/earthquake/nshmp/data/MutableXySequenceTests.java

.../java/gov/usgs/earthquake/nshmp/geo/json/GeoJsonTest.java

...a/gov/usgs/earthquake/nshmp/geo/json/PropertiesTests.java

...a/gov/usgs/earthquake/nshmp/model/SourceFeatureTests.java