Impacted versions:10

Steps to reproduce:
Following the code in https://www.odoo.com/documentation/10.0/api_integration.html both in a fresh install and against 'https://demo.odoo.com/start' trows a type error

Current behavior:
Now I get an error when executing:

```
ids = models.execute_kw(db, uid, password,  'res.partner', 'search',
    [[['is_company', '=', True], ['customer', '=', True]]],
    {'limit': 1})
[record] = models.execute_kw(db, uid, password,
    'res.partner', 'read', [ids])
# count the number of fields fetched by default
len(record)
```

In particular it seems to be a type error (cannot marshal class odoo.tools.float_utils.float_precision)

Expected behavior:
I would expect it to behave as in the documentation

openerp/fields.py
'column': None,                 
        'name': None,                   
        'model_name': None,             
        'comodel_name': None,           
        'store': True,                  
        'index': False,                 
        'manual': False,                
        'copy': True,                   
        'depends': (),                  
        'recursive': False,             
        'compute': None,                
        'compute_sudo': False,          
        'inverse': None,                
        'search': None,                 
        'related': None,                
        'related_sudo': True,           
        'company_dependent': False,     
        'default': None,                
        'string': None,                 
        'help': None,                   
        'readonly': False,              
        'required': False,              
        'states': None,                 
        'groups': None,                 
        'change_default': False,        
        'deprecated': None,             
        'related_field': None,          
        'group_operator': None,         
    }
    def __init__(self, string=Default, **kwargs):