rmcgibbo/mdtraj — pull request #429 by swails (2014-05-01 15:57:16+00:00)
Title: Fix reading in an Amber prmtop file as a topology when it has an ATOMIC_NUMBER section

Fixes the following exception:

```
/.../mdtraj/formats/prmtop.pyc
in load_prmtop(filename)
200 if 'ATOMIC_NUMBER' in raw_data:
201 try:
--> 202 element = elem.Element.get_by_atomic_number(int(raw_data['ATOMIC_NUMBER'][index]))
203 except KeyError:
204 element = None

AttributeError: type object 'Element' has no attribute 'get_by_atomic_number'
```