yaml: use selected user and not admin for onchange

Fixes: #1885
yaml: use selected user and not admin for defaults
only use alpha channel if it exists
[FIX] point_of_sale: fixed rounding issue for pos order when discount added(maintenance: 615322).
[FIX] hr,mail: correct remove of suggestions.
[IMP] stock: added missing 'context' parameter (opw 616952)
[FIX] stock_picking_wave: Missing _description
[FIX] Packaging: Debian: ignore root Makefile

Commit 388732dfa6a1 introduced a makefile at the root of the project, and
dh_auto_build is using this file instead of setup.py. Explicitely tell
debhelper to not use the makefile.
[FIX] point_of_sale: when loading models with a specified id, use read instead of search_read, to prevent inactive records from being skipped
[FIX] project_timesheet: missing timesheet for tasks without project

Timesheet activities (hr.analytic.timesheet) are generated when a work activity (project.task.work) is logged on a task.
These are updated if the project of the task is modified.
This patch applies the same behaviour for tasks without project, the timesheet activities are generated once a project is set on the task.
To avoid redundency in the code, extract the computation in a distinct method.
Fixes #701, opw 609481
[FIX] /web/binary/{image,saveas}: use request.registry instead of deprecated `request.session.model`

This makes the controllers work also for
public users, e.g. in the frontend.
[FIX] mrp: prevent suppression of bom if used in mo

The field bom_id is required on a manufacturing order and deleting a mrp.bom would block the current mo.
Restrict the suppression for manufacturing order in progress.
Fixes #3417
[FIX] project_timesheet: accept work without date

date field on a project.task.work is not required while it is on the hr.analytic.timesheet (with default value).
Avoid error if fill a task work without date, fallback on context_today.
[FIX] website_forum: avoid access error when closing spam/abuse questions

Logging the user login is not necessary, but
accessing it might cause access errors. Logging
the UID is equivalent anyway, so let's not bother.
[FIX] point_of_sale: correctly handle the rounding when the unit's rounding is set to zero
[FIX] point_of_sale: decimal precision was hardcoded to 2 in various places
[FIX] point_of_sale: some pos order fields were missing the proper decimal precision
[FIX] point_of_sale: use 'Product Price' decimal precision for product prices
[FIX] payment_*: typo, cliking -> clicking
[MERGE] forward port of branch 7.0 up to ab5ecef