astropy/astropy — pull request #437 by wkerzendorf (2012-10-16 16:36:57+00:00)
Title: NDData meta refactor

As previously discussed (#421) here's the refactor of the meta code.

At first I head the following for the `meta`-property:

```python
if isinstance(value, fits.Header):
self._meta = value
else:
self._meta = OrderedDict(value)
```

However when you pass a fits header to this it gets converted to an `OrderedDict` and does not retain some of the `Header` niceties: `hdr['OBSERVER'] == hdr['ObSeRvEr'] == hdr['observer']` which might be confusing.

So now I just check for `__getitem__` which is a poor mans check. Any ideas?