Bug 122850 Table/list should not be able to be inserted in Master Page mode.
Description: Table/list should not be able to be inserted in Master Page mode. Steps to reproduce: 1. New a report and transfer to Master Page mode. 2. New a datasource and dataset 3. Drag a list/table to page header/footer, bind it to dataset and drag some columns inside. 4. Save and preview Expected result: Insert list/table item in master page should be forbidden. Actual result: They are allowed and preview showed "undefine" in page
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
* one is the instance of <code>Exception</code>.
	 * 
	 * @return the list of exception
	 */
	public List getAllExceptions( )
	{
		return allExceptions;
	}
	/**
	 * Returns the validation executor.
	 * 
	 * @return the validation executor
	 */
	public ValidationExecutor getValidationExecutor( )
	{
		return validationExecutor;
	}
	/**
	 * Adds one validation listener. The duplicate listener will not be added.
	 * 
	 * @param listener
	 *            the validation listener to add
	 */
	public void addValidationListener( IValidationListener listener )
	{
		if ( validationListeners == null )
			validationListeners = new ArrayList( );
		if ( !validationListeners.contains( listener ) )
			validationListeners.add( listener );
	}