Use builder pattern and fluent interface to build Rugged instance.

checkstyle.xml

pom.xml

src/main/java/org/orekit/rugged/api/Rugged.java

src/main/java/org/orekit/rugged/api/RuggedBuilder.java

src/main/java/org/orekit/rugged/api/RuggedMessages.java

...resources/assets/org/orekit/rugged/RuggedMessages_de.utf8

...resources/assets/org/orekit/rugged/RuggedMessages_en.utf8

...resources/assets/org/orekit/rugged/RuggedMessages_es.utf8

...resources/assets/org/orekit/rugged/RuggedMessages_fr.utf8

...resources/assets/org/orekit/rugged/RuggedMessages_gl.utf8

...resources/assets/org/orekit/rugged/RuggedMessages_it.utf8

src/site/markdown/tutorials/direct-location-with-DEM.md

src/site/markdown/tutorials/direct-location.md

src/site/xdoc/changes.xml

src/test/java/org/orekit/rugged/api/RuggedBuilderTest.java

src/test/java/org/orekit/rugged/api/RuggedTest.java