Bug 140620 Chart scripting errors are ignored
Write a chart with an invalid script, the execution simply ignores the script. This makes it difficult to debug scripting. The error message is also not precise and needs improvements.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/script/ScriptHandler.java
+ " *            IChartScriptContext\n" 
			+ " */\n" 
			+ "//function beforeGeneration( chart, context ){}\n" 
			+ "\n" 
			+ "/**\n" 
			+ " * Called before the chart is rendered.\n" 
			+ " * \n" 
			+ " * @param gcs\n" 
			+ " *            GeneratedChartState\n" 
			+ " * @param context\n" 
			+ " *            IChartScriptContext\n" 
			+ " */\n" 
			+ "//function beforeRendering( gcs, context ){}\n" 
			+ "\n" 
			+ "/**\n" 
			+ " * Called before drawing each block.\n" 
			+ " * \n" 
			+ " * @param block\n" 
			+ " *            Block\n" 
			+ " * @param context\n" 
			+ " *            IChartScriptContext\n" 
			+ " */\n" 
			+ "//function beforeDrawBlock( block, context ){}\n" 
			+ "\n" 
			+ "/**\n" 
			+ " * Called before drawing each entry the legend.\n" 
			+ " * \n" 
			+ " * @param label\n" 
			+ " *            Label\n" 
			+ " * @param context\n"