Merge branch 'issue-474' into develop

src/main/java/org/orekit/errors/OrekitMessages.java

...main/java/org/orekit/files/ccsds/ndm/AbstractBuilder.java

src/main/java/org/orekit/files/ccsds/ndm/ParserBuilder.java

src/main/java/org/orekit/files/ccsds/ndm/WriterBuilder.java

src/main/java/org/orekit/files/ccsds/ndm/adm/AdmParser.java

...ain/java/org/orekit/files/ccsds/ndm/adm/AttitudeType.java

...in/java/org/orekit/files/ccsds/ndm/adm/aem/AemParser.java

...in/java/org/orekit/files/ccsds/ndm/adm/aem/AemWriter.java

...ava/org/orekit/files/ccsds/ndm/adm/aem/AttitudeEntry.java

...main/java/org/orekit/files/ccsds/ndm/adm/apm/ApmFile.java

...in/java/org/orekit/files/ccsds/ndm/adm/apm/ApmParser.java

...in/java/org/orekit/files/ccsds/ndm/adm/apm/ApmWriter.java

...in/java/org/orekit/files/ccsds/ndm/odm/ocm/OcmParser.java

...in/java/org/orekit/files/ccsds/ndm/odm/ocm/OcmWriter.java

...in/java/org/orekit/files/ccsds/ndm/odm/oem/OemParser.java

...in/java/org/orekit/files/ccsds/ndm/odm/oem/OemWriter.java

...in/java/org/orekit/files/ccsds/ndm/odm/omm/OmmParser.java

...in/java/org/orekit/files/ccsds/ndm/odm/omm/OmmWriter.java

...in/java/org/orekit/files/ccsds/ndm/odm/opm/OpmParser.java

...in/java/org/orekit/files/ccsds/ndm/odm/opm/OpmWriter.java