Merge branch 'imt-edits-235' into 'main'

...va/gov/usgs/earthquake/nshmp/gmm/AbrahamsonEtAl_2014.java

...in/java/gov/usgs/earthquake/nshmp/gmm/BooreEtAl_2014.java

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

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

src/main/java/gov/usgs/earthquake/nshmp/gmm/Idriss_2014.java

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

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

...ava/gov/usgs/earthquake/nshmp/gmm/UsgsDampingScaling.java

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

src/main/resources/gmm/coeffs/Idriss14.csv

src/main/resources/gmm/tables/nga-east-Graizer16.dat

src/main/resources/gmm/tables/nga-east-Graizer17.dat

src/main/resources/gmm/tables/nga-east-PEER_GP.dat

src/main/resources/gmm/tables/nga-east-PZCT15_M1SS.dat

src/main/resources/gmm/tables/nga-east-PZCT15_M2ES.dat

src/test/java/gov/usgs/earthquake/nshmp/gmm/ImtTest.java

...test/java/gov/usgs/earthquake/nshmp/gmm/InstanceTest.java