Merge branch 'develop' into dsst-od

Conflicts:
	pom.xml
	src/main/java/org/orekit/estimation/leastsquares/BatchLSEstimator.java
	src/main/java/org/orekit/propagation/conversion/NumericalPropagatorBuilder.java
	src/main/java/org/orekit/propagation/integration/AbstractIntegratedPropagator.java
	src/main/java/org/orekit/propagation/integration/FieldAbstractIntegratedPropagator.java
	src/main/java/org/orekit/propagation/integration/FieldAdditionalEquations.java
	src/main/java/org/orekit/propagation/numerical/DSConverter.java
	src/main/java/org/orekit/propagation/semianalytical/dsst/forces/AbstractGaussianContribution.java
	src/main/java/org/orekit/propagation/semianalytical/dsst/forces/DSSTSolarRadiationPressure.java