Bug 208055 [Markers] Need a sorting method for the markers view
As there is currently no accessible way to change sort order or direction. A menu should be enough.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/provisional/views/markers/MarkerContentGenerator.java
* 
	 * @param field
	 * @return int one of {@link MarkerComparator#ASCENDING} or
	 *         {@link MarkerComparator#DESCENDING}
	 */
	int getSortDirection(MarkerField field) {
		if (getComparator().descendingFields.contains(field))
			return MarkerComparator.DESCENDING;
		return MarkerComparator.ASCENDING;
	}
	/**
	 * Set the memento of the receiver.
	 * 
	 * @param memento
	 */
	void setMemento(IMemento memento) {
		this.memento = memento;
	}
	/**
	 * Save the state of the receiver to memento
	 * 
	 * @param memento
	 */
	void saveState(IMemento memento) {
		getComparator().saveState(memento);
	}
	/**
	 * Get the markerGroups associated with the receiver.
	 * 
	 * @return Collection of {@link MarkerGroup}