Optimisations et fix de bugs

res/stages/data-view-stage.fxml

res/stages/display-settings-stage.fxml

...ille/sae/classification/controller/AddDataController.java

...sae/classification/controller/AxesSettingsController.java

...le/sae/classification/controller/DataStageController.java

.../classification/controller/DisplaySettingsController.java

...lle/sae/classification/controller/LoadDataController.java

...le/sae/classification/controller/MainStageController.java

...ivlille/sae/classification/model/ClassificationModel.java

...main/java/fr/univlille/sae/classification/model/Iris.java

...a/fr/univlille/sae/classification/model/LoadableData.java

...ava/fr/univlille/sae/classification/view/AddDataView.java

...r/univlille/sae/classification/view/AxesSettingsView.java

...a/fr/univlille/sae/classification/view/DataStageView.java

...a/fr/univlille/sae/classification/view/MainStageView.java