[FIX] ir.ui.view: deletion of parent view should not cascade

This is safer to avoid inadvertently dropping customizations,
and does not impact the normal update/uninstall process, which
is based on the dependency order.
[FIX] product: comparison of currency rounding

Setting 0.0001 as precision used to be converted to 9.999999999999999e-05
precision_digits of 6 is the precision of the field 'rounding' on res.currency
Fixes #3875
[FIX] website: the attachment creation improvment of a3e578068e170df41ef95c00026bc2351c9e2c13 must be done on res_model

instead of type
Merge branch '8.0' of https://github.com/odoo/odoo into 8.0-linux64