Bug 213126 Add support for DataEngine-leve dataset cache
In many cases the DataEngine-leve dataset cache is useful which ensure that a dataset is executed one time during rendering one report. To support this feature a new dataset property should be added. The Birt customer can choose whether this dataset need to be cached or not by setting the property in deisgn time.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/writer/ModuleWriter.java
value, false );
				else
					writeLongIndentText( DesignSchemaConstants.PROPERTY_TAG,
							OdaDesignerState.CONTENT_AS_BLOB_MEMBER, value );
			}
		}
		catch ( UnsupportedEncodingException e )
		{
			assert false;
		}
		writer.endElement( );
	}
	/**
	 * Writes the content tree out to the file.
	 * 
	 * @param tree
	 *            the tree to write out
	 */
	protected void writeContentTree( ContentTree tree )
	{
		if ( tree == null || tree.isEmpty( ) )
			return;
		List children = tree.getChildren( );
		for ( int i = 0; i < children.size( ); i++ )
		{
			ContentNode node = (ContentNode) children.get( i );
			writeContentNode( node );
		}
	}
	/**