solved symbol size trunc bug thanks to tbonfort

symbol values with fractional size were truncated

here a test sld: https://gist.github.com/luipir/5964556
where <se:Size>0.7</se:Size> were truncated in: SIZE 0

as suggested by: EvenR changed nSize in dSize "to indicate the change of type"

solution has been found in #mapserver chat