Bpython exits if parenthese is typed after a property raising exception

The following session results in bpython==0.12 exiting and dumping the exception raised by the user code.

```
#!python

>>> class A:
...   @property
...   def a(self): return 1/0
... 
>>> a=A()
>>> a.a(
```

---
- Bitbucket: https://bitbucket.org/bobf/bpython/issue/281
- Originally Reported By: Anonymous
- Originally Created At: 2014-05-06T13:22:26.672
