Bug 210496 Add hasStyle property in reportItemModel extension point
When chart gets reportItem's properties by extending ReportItem, style properties are null. Hence, model needs to add hasStyle property in reportItemModel extension point
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/metadata/ElementDefn.java
* Said another way, type system inheritance uses Java-like class inheritance.
 * User-element inheritance uses JavaScript-like prototype inheritance.
 * <p>
 * BIRT does define and "extended element" that the user can define from
 * scratch, but even this follows the same rules. An extended element is not a
 * new type, it is just a particular set of customizations of the predefined
 * "extended" type.
 * <p>
 * User-defined inheritance is limited to elements of the same type. A label can
 * extend another label, but it cannot extend a data element, say.
 * <p>
 * System inheritance is used to define properties in a base class that should
 * be inherited by derived classes. User-inheritance implicitly inherits
 * properties, but focuses on inheriting property values. That is, user
 * inheritance allows Label B to inherit a font color of red from Label A. As
 * noted above, elements can define user properties. These property definitions
 * also are inherited with user inheritance. that is, if Label A defines a new
 * "Blink Rate" property, then label B (which extends label A) also has this
 * property.
 * 
 * <h3>Styles</h3>
 * 
 * BIRT includes the idea of styles. A style is simply a set of visual
 * information defined once in a design but used by many elements. At the core
 * level that we are discussing here, styles introduce a couple of interesting
 * twists to the design of the meta-data and element systems.
 * <p>
 * First some element types are defined to "have" a style. Having a style means
 * two things. First, the user can specify the name of a shared style to
 * associate with the element. Second, means that the element logically has a