Creates new create methods for Task and TaskGroup

TaskSource has two new methods. One method for create a Task and other for create a TaskGroup
assinging them to the TaskSource.
Task has one new method to create a task without initialize its dates.

FEA: ItEr77S05BasicProjectImport

libreplan-business/src/main/java/org/libreplan/business/orders/entities/TaskSource.java

@@ -52,6 +52,29 @@ public class TaskSource extends BaseEntity {
         return result;
     }
 
+    /**
+     * Needed for import external tasks.
+     *
+     * @return Task New Task
+     */
+    public Task createTaskWithoutDatesInitializedAndLinkItToTaskSource() {
+        TaskElement task = Task.createTaskWithoutDatesInitialized(this);
+        this.setTask(task);
+        return (Task) task;
+    }
+
+    /**
+     * Needed for import external tasks.
+     *
+     * @return Task New Task
+     */
+    public TaskGroup createTaskGroupWithoutDatesInitializedAndLinkItToTaskSource() {
+        TaskElement task = TaskGroup.create(this);
+        this.setTask(task);
+        return (TaskGroup) task;
+    }
+
+
     public static TaskSourceSynchronization mustAdd(
             TaskSource taskSource) {
         return new TaskSourceMustBeAdded(taskSource);

libreplan-business/src/main/java/org/libreplan/business/planner/entities/Task.java

@@ -96,6 +96,24 @@ public class Task extends TaskElement implements ITaskPositionConstrained {
         return result;
     }
 
+    /**
+     * Needed for import external tasks.
+     *
+     * Creates a Task without initializing the dates.
+     *
+     * @param taskSource
+     *            TaskSouce for create the task
+     *
+     * @return Task New Task
+     */
+    public static Task createTaskWithoutDatesInitialized(TaskSource taskSource) {
+        Task task = new Task();
+        OrderElement orderElement = taskSource.getOrderElement();
+        orderElement.applyInitialPositionConstraintTo(task);
+        Task result = create(task, taskSource);
+        return result;
+    }
+
     @Override
     protected void initializeDates() {
         EffortDuration workHours = EffortDuration.hours(getWorkHours());