Bug 173236 NPE is thrown when opening a design file that is created by a higher version BIRT
1. New a report, switch to xml-source view. 2. Edit the version number in line 2, from 3.2.10 to 3.2.11 and save. 3. Close the report and reopen it. The xml-source view is opened automatically. Switch to lay-out view, there's an error message window, and NPE is thrown in error-log view. When user is trying to open a design file that is created by a higher version BIRT, model will throw an exception and stop parsing the report design file. UI should 1. Prevent the NPE 2. Telling user that he is using a higher version design file that this build does not support. (Catch the exception and reflect the message in the exception to end user)
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/parser/DesignParserException.java
/**
	 * Use of "extends" to reference a style when "name" should be used.
	 */
	public static final String DESIGN_EXCEPTION_ILLEGAL_EXTENDS = MessageConstants.DESIGN_PARSER_EXCEPTION_ILLEGAL_EXTENDS;
	/**
	 * Image item has more then one kind of reference type.
	 */
	public static final String DESIGN_EXCEPTION_IMAGE_REF_CONFLICT = MessageConstants.DESIGN_PARSER_EXCEPTION_IMAGE_REF_CONFLICT;
	/**
	 * Image reference type is expression, but not both type expression and
	 * value expression are present in the design file.
	 */
	public static final String DESIGN_EXCEPTION_INVALID_IMAGEREF_EXPR_VALUE = MessageConstants.DESIGN_PARSER_EXCEPTION_INVALID_IMAGEREF_EXPR_VALUE;
	/**
	 * Image URL value is empty.
	 */
	public static final String DESIGN_EXCEPTION_INVALID_IMAGE_URL_VALUE = MessageConstants.DESIGN_PARSER_EXCEPTION_INVALID_IMAGE_URL_VALUE;
	/**
	 * One property is not encryptable.
	 */
	public static final String DESIGN_EXCEPTION_PROPERTY_IS_NOT_ENCRYPTABLE = MessageConstants.DESIGN_PARSER_EXCEPTION_PROPERTY_IS_NOT_ENCRYPTABLE;
	/**
	 * Image Name is empty.
	 */
	public static final String DESIGN_EXCEPTION_INVALID_IMAGE_NAME_VALUE = MessageConstants.DESIGN_PARSER_EXCEPTION_INVALID_IMAGE_NAME_VALUE;
	/**
	 * An action Drillthrough is missing the "reportName" value.
	 */
	public static final String DESIGN_EXCEPTION_ACTION_REPORTNAME_REQUIRED = MessageConstants.DESIGN_PARSER_EXCEPTION_ACTION_REPORTNAME_REQUIRED;
	/**