Fix lang_IT handling of floats (#143)

`n % 1 != 0` is not a valid test for float:

In []: 1.1 % 1 == 0
Out[]: False

but:

In []: 1.0 % 1 == 0
Out[]: True

hence it's really necessary to explicitly test for type in this case.

num2words/lang_IT.py

@@ -169,7 +169,7 @@ class Num2Word_IT:
     def to_cardinal(self, number):
         if number < 0:
             string = Num2Word_IT.MINUS_PREFIX_WORD + self.to_cardinal(-number)
-        elif number % 1 != 0:
+        elif isinstance(number, float):
             string = self.float_to_words(number)
         elif number < 20:
             string = CARDINAL_WORDS[number]