enhance tip date import from Nexus file CompEvol/beast2#1194

Author: rbouckaert

src/beastfx/app/inputeditor/BeautiDoc.java

@@ -1089,6 +1089,9 @@ public void addTraitSet(TraitSet trait) {
                         // TODO: this might not be a valid type conversion from TreeInterface to Tree
                         Tree tree = (Tree) ((GenericTreeLikelihood) d).treeInput.get();
                         tree.m_traitList.setValue(trait, tree);
+                        List<TraitSet> list = new ArrayList<>();
+                        list.add(trait);
+                        tree.processTraits(list);
                     } catch (Exception e) {
                         e.printStackTrace();
                     }

src/beastfx/app/inputeditor/NexusImporter.java

@@ -71,6 +71,9 @@ public List<BEASTInterface> loadFile(File file) {
 					selectedBEASTObjects.addAll(parser.calibrations);
 				}
 			}
+			if (parser.traitSet != null) {
+				selectedBEASTObjects.add(parser.traitSet);
+			}
 		} catch (Exception ex) {
 			ex.printStackTrace();
 			Alert.showMessageDialog(null, "Loading of " + file.getPath() + " failed: " + ex.getMessage());