Separate iterations and evaluations counters.

.../org/orekit/estimation/leastsquares/BatchLSEstimator.java

...a/org/orekit/estimation/leastsquares/BatchLSObserver.java

...rg/orekit/estimation/leastsquares/MeasurementHandler.java

src/main/java/org/orekit/estimation/leastsquares/Model.java

...ava/org/orekit/estimation/leastsquares/ModelObserver.java

...g/orekit/estimation/measurements/AbstractMeasurement.java

...main/java/org/orekit/estimation/measurements/Angular.java

...n/java/org/orekit/estimation/measurements/Evaluation.java

.../java/org/orekit/estimation/measurements/Measurement.java

src/main/java/org/orekit/estimation/measurements/PV.java

src/main/java/org/orekit/estimation/measurements/Range.java

...in/java/org/orekit/estimation/measurements/RangeRate.java

src/test/java/org/orekit/estimation/EstimationTestUtils.java

.../orekit/estimation/leastsquares/BatchLSEstimatorTest.java

...st/java/org/orekit/estimation/leastsquares/ModelTest.java

.../java/org/orekit/estimation/measurements/AngularTest.java

...est/java/org/orekit/estimation/measurements/BiasTest.java

...org/orekit/estimation/measurements/GroundStationTest.java

.../org/orekit/estimation/measurements/IonoModifierTest.java

...ava/org/orekit/estimation/measurements/RangeRateTest.java