[FIX] analytic_user_function: inherit conflict on account type

The field account_id was inherited with position="replace" meaning we erased
future changes made into hr_timesheet_sheet (41f2eba missed "type in []" and
65f31b9 missed use_timesheets).
Replace by position="attributes" to only change what matters: the on_change.
Fixes #3974
[FIX] website: responsive images in table for Firefox only

It looks there is a bug in Firefox concerning responsive images in table. See bugzilla https://bugzilla.mozilla.org/show_bug.cgi?id=975632
Bootstrap advises to use width: 100% for .img-responsive as workaround were needed.
The @moz-document is to apply this for Mozilla only.

opw-617582
opw-618659
Merge branch '8.0' of https://github.com/odoo/odoo into 8.0-win32