Bug 213671 Expose evaluate() method in IReportContext
Need Engine expose evaluate() method in IReportContext interface, this will be used to evaluate global Javascript expression in case there's no resultset bound to current report item.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/script/IReportContext.java
{
	/**
	 * return the report runnable used to create/render this report
	 * 
	 * @return
	 */
	IReportRunnable getReportRunnable( );
	/**
	 * 
	 * @param name
	 * @return
	 */
	Object getParameterValue( String name );
	/**
	 * 
	 * @param name