Bug 100889 [Undo] - AbstractOperation toString() appends bogus comma
The toString() on AbstractOperation puts commas between undo contexts, and also puts one at the end. It looks pretty bogus in the operation history view. Should clean up to not add the very last comma.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/AbstractOperation.java
*      <p> Default implementation. Subclasses may override this method.
	 *      </p>
	 */
	public boolean canRedo() {
		return true;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#canUndo()
	 *      <p> Default implementation. Subclasses may override this method.
	 *      </p>
	 */
	public boolean canUndo() {
		return true;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#dispose()
	 *      <p> Default implementation. Subclasses may override this method.
	 *      </p>
	 */
	public void dispose() {
		
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#execute(org.eclipse.core.runtime.IProgressMonitor,