Percentage token has .tvalue as float

- `str` was expected
- e.g. `=IF(RANGE>75%; 1; 0)` fails since `75%` is translated to .75
- while `=IF(RANGE>.75; 1; 0)` would translate to '0.75'

koala/ast/astnodes.py

@@ -317,7 +317,7 @@ def emit(self,ast,context=None, pointer = False):
             childs = args[0].children(ast)
 
             for child in childs:
-                if ':' in child.tvalue and child.tvalue != ':':
+                if ':' in str(child.tvalue) and child.tvalue != ':':
                     is_range = True
                     range = child.tvalue
                     break