Bug 207120 Please model provide an API for data type conversion.
Currently, there're two data types: column data type and parameter data type. But they're inconsistent. Could model provide APIs for conversion between the two types. Thanks. In addition: please check the code into head and 2.2.1 branch, because we have a 2.2.1 bug to fix.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleUtil.java
{
		/**
		 * 
		 * @param os
		 * @param signature
		 * @throws IOException
		 */
		public SectionXMLWriter( OutputStream os, String signature )
				throws IOException
		{
			super( );
			out = new PrintStream( os, false, OUTPUT_ENCODING );
		}
	}
	/**
	 * Write an action into a stream in UTF-8 encoding.
	 */
	private static class ActionWriter extends ModuleWriter