(SEPARATOR) AttributeError: 'AttrMap' object has no attribute 'id_path'

I'm using watches, and stepping using continue (`c`)...

``` py
File "/usr/lib64/python2.7/bdb.py", line 49, in trace_dispatch
return self.dispatch_line(frame)
File "pudb/debugger.py", line 173, in dispatch_line
self.user_line(frame)
File "pudb/debugger.py", line 371, in user_line
self.interaction(frame)
File "pudb/debugger.py", line 339, in interaction
show_exc_dialog=show_exc_dialog)
File "pudb/debugger.py", line 2059, in call_with_ui
return f(*args, **kwargs)
File "pudb/debugger.py", line 2269, in interaction
self.event_loop()
File "pudb/debugger.py", line 2235, in event_loop
toplevel.keypress(self.size, k)
File "pudb/ui_tools.py", line 83, in keypress
result = self._w.keypress(size, key)
File "urwid/container.py", line 1128, in keypress
return self.body.keypress( (maxcol, remaining), key )
File "urwid/container.py", line 2269, in keypress
key = w.keypress((mc,) + size[1:], key)
File "pudb/ui_tools.py", line 83, in keypress
result = self._w.keypress(size, key)
File "urwid/container.py", line 1587, in keypress
key = self.focus.keypress(tsize, key)
File "urwid/container.py", line 1587, in keypress
key = self.focus.keypress(tsize, key)
File "pudb/ui_tools.py", line 88, in keypress
return handler(self, size, key)
File "pudb/debugger.py", line 754, in change_var_state
.get_inspect_info(var.id_path, read_only=False)
AttributeError: 'AttrMap' object has no attribute 'id_path'
```

``` py
>>> var.get_attr_map()
{None: 'variable separator'}
>>> key
'c'
```

```
SEPARATOR = urwid.AttrMap(urwid.Text(""), "variable separator")
```

Start in pudb/debugger.py at change_var_state, where the traceback shows var.id_path being passed to get_inspect_info, and compare that with the SEPARATOR definition shown in the issue. Reproduce the failure while using a watch and pressing c; done means continuing no longer raises this AttributeError and variable separators still display correctly.

Written by the indexing model from the issue text.