7.0 add price propreties based

3 modules

Easing properties input in sale order line
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This modules simplifies the input of properties in the sale order line and
other places.

For instance, in the many2many field 'property_ids', it allows the user to
digit 'width 0.5' and the system will automatically create a property of group
'width' with value '0.5'

It also adds the model 'mrp.property.formula', to be used by computations based
on properties.
Used by modules like 'product_price_properties_based'

Dynamic fields for sale order line properties
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This module allows to dynamically draw properties groups on sale order lines.
That is, if you have a property group 'Length' and set it as 'Draw dynamically',
the module will automatically add the x_length field to the sale order line and
visualize it as char field in the form view.
When fill the 'Length' field, the module will update the properties field (property_ids)
according to it.
This allows to set the line's properties through normal fields, instead of creating
new properties or selecting existing properties.

Product price properties based
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This module allows to use python formaulas to compute the sale order line
price.

You can configure the 'Price formula' on the product form using python code.

Formula example:
```
area = float(properties['Width']) * float(properties['Length'])
result = area / 2.0
if 'Painting' in properties:
    result = result + 5
```

When changing properties on sale order line, the system will automatically
compute the line price unit.