Update fields positions and boundaries for parsing pdf statements. Rewrite xml parsing logic.

Hi,

I've tried using your aib2ofx, but that failed initially. After some poking, I was able to get the wanted results by at least:
- changing the fields and page boundaries in pdfparse.py
- changing 'elm.string' to "s = ' '.join(elm.findAll(text=True)).strip()" in multiple places.

Also while figuring out the code, I've rewritten most of the xml iteration logic, which I believe makes it more readable. I realise that currently this might not look too fancy, but hopefully this contributes some useful ideas for further development.