Idea: This should be improved to reuse proxyfied field method
        instead directly.

  This is required by Listbox for example in order to cache per list_start.

  Use OFS.Cache.Cachable to cache result outcome (html) of forms and
  fields for ERP5Form.

  Include Cacheable setup on ZMIField and extend render_htmlgrid.

Added aggregate item and item creations actions on new portal types.

Implemented Returned Orders like any other Order.

 Fix Image Conversion by using sRGB instead RGB, because it seems that using
 'sRGB' instead of 'RGB' makes a good result for RGB input, because imagemagick
 assume that input's colorspace is sRGB if not specified.

It includes minor improvements.

 Introduce temp_object parameter on builder.build() and propagate it
 over until the newContent() calls. This change allow use create
 Temporary Documents intestead real ones, like a "preview".

Person information must be consistent, so it allow any project define appropriate constraints.
You can only progress if you are logged in, otherwise show a button to user to login form.

Renamed SaleOrder_finalizeShopping to WebSection_finalizeShopping.

* This commit should be rebased before be really released.

SaleOrder_viewConfirmAsWeb is a duplication of SaleOrder_viewAsWeb

Enable SaleOrder_isShippingRequired implementation
Optimize SaleOrder_isShoppingCartEmpty

We use field instead to present such information.

- SaleOrder_viewAsWeb (previously SaleOrder_viewDetailAsWeb) is now the SaleOrder_view in web mode, where it is used to view the previous Sale Orders informations.
- WebSection_viewShoppingCart is now the shopping cart (previously was calledSaleOrder_viewAsWeb)

- Introduce improvements on current forms in meanwhile.

Fix name convention on forms and use login_form instead register section for request the user login.

- Removed unused code which has no meaning to keep (Just ramdom scrips)
- Moved to erp5_commerce_paypal_legacy code only used by PayPal Legacy related code.