[IMP] add odoo.py shell subcommand

It starts an interactive Python console. If a database is provided, with the
`-d` argument `env` is bound to an Environement with the uid and context of
SUPERUSER_ID and `self` is bound to a RecordSet of the corresponding res.users.

Courtesy of Daniel Reis, reworked to be a bit more agnostic.

Command class is moved from __init__.py to command.py to improve imports of
__init__.py
[IMP] crm deduplicate contacts view

Move buttons to the footer.

Closes: #562
[IMP] SEO on product categories
[ADD] ir_actions add logging to server actions

The log(message, level='info') function will create ir_logging records, useful
to debug server actions.

Closes: #928
[IMP] account, restrict removal of accounts used on account.tax

Closes: #789
[IMP] ir.attachment access right, use write mode of related object

For related models, check if we can write to the model, as linking
or unlinking attachments can be seen as an update to the model.

Courtesy of Vincent Vinet

Closes: #1035
[FIX] server report_configuration database

Report unix socket instead of localhost when using named sockets.

Courtesy of Leonardo Pistone

Closes: #1899, #1900
[IMP] auth_signup: inform users about signup email validity

Closes #4303
[IMP] base: better evaluation context on menu

Allow more complex evaluations (e.g. using time) in domain of ir.ui.menu.
Move _get_eval_context to ir.actions.actions for basic context elements.
opw 603382
[IMP] web: better content-type for attachments

Add the corresponding content type document instead the default content type.
This allows browser to detect the type of file being downloaded.
Fixes #1225
[IMP] point_of_sale: make the floor plan background fit the floor