[FIX] web: correct display of dropdown arrows in ie11
[FIX] website_sale: right number of products in the page

The goal is to fill the page with at least 20 products and to fill all grid lines
Thus, the page should be filled with products until there are 20 products and all lines of the grid are full.
[MERGE] forward port of branch 7.0 up to 8e76938
[FIX] web: remove enforceFocus method from bootstrap modal since it is conflicting with other non bootstrap element

This method trigger the focus event when clicking inside the modal, causing a blur event on other widgets resulting in unwanted problem. Typical case is for the jquery datetimepicker where we try to open a select element which will close right after.
[FIX] crm_partner_assign: colors only if there is a stage on the lead
[FIX] website_sale: check the first product variant radio button in variants list by default to avoid users to click on Add to Cart without choosing any variant
[FIX] account: tax report: translate account.tax.code according to context

As get_lines is called from the template, use a partial to embed the original context.
[FIX] calendar: avoid to pass ids as string to unlink and write methods

opw-616532: if the event is associated somehow to a workflow, an assert is done to check that element of the ids list are (int, long)
[MERGE] forward port of branch saas-3 up to 2c1bcfb
[FIX] Render of report shouldn't update context

With API 8 context is frozendict that don't support update