FIX: Fix naming for numpy/pandas/windows

When I tried using `pyeparse` under windows, I hit an error any time I tried to read a `raw` file:
```
ValueError: mismatch in size of old and new data-descriptor
```
This has something to do with how we use mixed-type arrays/pandas. I don't completely understand the issue, but this fixes it.

With this patch, tests pass under Windows 32-bit Python 2.7.