Fix Issue #75: Catch TypeError in marshalling

When marshalling receiving a `MarshallingError` is much more useful than
receiving the underlying exception directly as the `MarshallingError`
has context about where it happened and it means all marshalling issues
can be handled in one place.

This change also catches `TypeError`s from the int and float formatters
so that they are correctly turned into `MarshallingError`s.

Author: robyoung

flask_restx/fields.py

@@ -459,7 +459,7 @@ def format(self, value):
             if value is None:
                 return self.default
             return int(value)
-        except ValueError as ve:
+        except (ValueError, TypeError) as ve:
             raise MarshallingError(ve)
 
 
@@ -473,7 +473,7 @@ class Float(NumberMixin, Raw):
     def format(self, value):
         try:
             return float(value)
-        except ValueError as ve:
+        except (ValueError, TypeError) as ve:
             raise MarshallingError(ve)