res_partner_fiscal_document is borne

Hello, this is my first small contribution. I hope the quality is somewhat on the level that is expected.
It registeres legal documents with their number and the document type on partners and is thougth for countries which need such type of identification for legal purposes. The user can ubload the document to be able to proove, he is in the possesion of a scan of it.

The more interesting part for further customization are the hooks for formatting and validation of the different document numbers as to local habtis or in order to copy it for compatibility reasons in a different format to another field...

Related Bugs: 
Binnary File Field https://github.com/odoo/odoo/issues/1526
Access of super() field, but actually this might just be ignorance of mine... However, I tried arround two days now. https://github.com/odoo/odoo/issues/1530

I think I need still feedback on the access rule part.
Who should be able to create new document types?
 - Nobody (only csv-file load at install)?
 - Administrator?
 - Financial manager?

This module was developed in the focus of colombian legal requirements, but all the localization parts have been stripped off.

Thanks in advance for your feedback!
@nhomar @bwrsandman
@rvalyi, maybe you have such strange things too in brasil? :)
```
self._copyid(self)  ->  _copyid(self)
@staticmethod  -> deleted
```

The truth is, I did not fully get the concept of static and classmethods. I dont understand the explications given on the internet. It doesn't seem a difficult concept but explications are made complex...

Is there a rule of thumb in the odoo context?