Bug 161383 Support page-break-inside property on report item
Need support page-break-inside property on report items
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/metadata/ElementDefn.java
* property definitions. The element definition (ElementDefn) defines the set of
 * properties available on that element.</dd>
 * 
 * <dt><strong>Property value </strong></dt>
 * <dd>A property value is the actual value that the user sets for a property.
 * A property value is associated with a element, and is stored in the
 * <code>DesignElement</code> class, or one of its subclasses. For
 * convenience, we often use the word "property" to mean a property value.
 * Property values can be in two states: set or unset. An unset value generally
 * causes the model to inherit the property value from the parent element (if
 * any). Properties in BIRT work much like properties in JavaScript objects.
 * </dd>
 * </dl>
 * 
 * <h3>System and User Properties</h3>
 * 
 * BIRT defines a wide range of element types, each with a wide range of
 * properties. Properties defined by BIRT itself are called
 * <em>system properties</em>. They are defined as part of the element type
 * definition in the meta-data file. System properties are of two types: normal
 * or <em>intrinsic</em>. An intrinsic property is one defined by a member
 * variable the DesignElement class or one of its subclasses. An normal property
 * is stored as a name/value pair in the DesignElement class.
 * <p>
 * BIRT also allows users to define their own properties. Such properties are
 * called, unsurprisingly, user properties. User properties are defined on an
 * element and are available to that element, and any elements that derive from
 * that element (see below.)
 * <p>
 * For the most part, system and user properties are defined in the same way as