Completed parsing of ICGEM V2.0 format for piecewise gravity fields.

src/changes/changes.xml

...rg/orekit/forces/gravity/potential/ICGEMFormatReader.java

...forces/gravity/potential/PotentialCoefficientsReader.java

...rekit/forces/gravity/potential/TimeDependentHarmonic.java

...rekit/forces/gravity/potential/ICGEMFormatReaderTest.java

...urces/potential/icgem-format/corrupted-01-g007_eigen_coef

...urces/potential/icgem-format/corrupted-02-g007_eigen_coef

...urces/potential/icgem-format/corrupted-03-g007_eigen_coef

...urces/potential/icgem-format/corrupted-04-g007_eigen_coef

...urces/potential/icgem-format/corrupted-05-g007_eigen_coef

...urces/potential/icgem-format/corrupted-06-g007_eigen_coef

...urces/potential/icgem-format/corrupted-07-g007_eigen_coef

...urces/potential/icgem-format/corrupted-08-g007_eigen_coef

...urces/potential/icgem-format/corrupted-09-g007_eigen_coef

...t/resources/potential/icgem-format/corrupted-10-eigen-6s4

...t/resources/potential/icgem-format/corrupted-11-eigen-6s4

...t/resources/potential/icgem-format/corrupted-12-eigen-6s4

...t/resources/potential/icgem-format/corrupted-13-eigen-6s4

...esources/potential/icgem-format/dummy_invalid_error_icgem

...resources/potential/icgem-format/dummy_invalid_norm_icgem