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.

tests/test_it.py

@@ -22,7 +22,6 @@ from num2words import num2words
 
 
 class Num2WordsITTest(TestCase):
-
     maxDiff = None
 
     def test_negative(self):
@@ -225,3 +224,11 @@ class Num2WordsITTest(TestCase):
             "novecentouno miliardi, duecentotrentaquattro milioni e "
             "cinquecentosessantasettemilaottocentonovantesimo"
         )
+
+    def test_with_decimals(self):
+        self.assertAlmostEqual(
+            num2words(1.0, lang="it"), "uno virgola zero"
+        )
+        self.assertAlmostEqual(
+            num2words(1.1, lang="it"), "uno virgola uno"
+        )