Formats the value to the specified number of decimal places.

DecimalFormatter is typically used in the XML Renderer Framework, but can be invoked programmatically as in the following example which evaluates to '3.142':

If you are using this formatter in conjunction with the ThousandsFormatter in a localised application, please ensure this DecimalFormatter comes before the ThousandsFomatter in the renderer xml, otherwise localised decimal point characters will stop the DecimalFormatter from recognising the number.

DecimalFormatter.format(3.14159, {dp:3})