Migration of l10n_ch_bank and l10n_ch_zip

Supersedes https://github.com/OCA/l10n-switzerland/pull/62

I worked on top of the @BT-olivier's branch and changed those things:

* Cleanings (usage of string literals instead of docstrings, ...)
* Use the new API
* The wizard to update the banks do no longer needs to create a temporary file
* The xmlids for the banks must be created in the l10n_ch_bank namespace, not in l10n_ch,
  correct the history with a migration
* Convert date fields to fields.Date
* Add again the record which where in the 7.0 files but add them as 'active=False' so
  they for the ones who migrate, they will be deactivated instead of deleted
* remove the *_old modules
* restore the `ir.country.state` which have been dropped during the module's migration
* The xmlids of the `res.better.zip` have been changed from the 7.0 version. I restored all of them (using this script https://gist.github.com/guewen/34fbc497297a1af0ca2f)
Bonjour, 

Il semble que le commentaire de ce module soit celui de l10n_ch_zip, pas l10n_ch_bank !?!? 

----- Mail original -----

| In l10n_ch_bank/__openerp__.py: > -============================
| > -
| > - This module will load all Swiss postal codes (ZIP) in Odoo to >
| > -ease the input of partners.

Avec mes plus sincères salutations, 

Jean-Marc Vandel 
Senior Project Manager 

Open Net Sàrl 
Rue de l'Industrie 59 
CH-1030 Bussigny 

www.open-net.ch 
+41 79 212.65.94 
jmv@open-net.ch