The registry loading system should not alter databases unless it is
asked to do so, by a module installation or update instruction.
This property should hold true as well for database bootstrap, and this
is what this commit changes..

In order to avoid any behavior change for command-line users, an
implicit `-i base` is assumed when starting the server from the
command-line with `-d <db>`, causing the db boostrap to happen if the
database did not exist yet.

In Python 3, ``print`` becomes a builtin function. This is available
in Python 2 by importing the ``print_function`` feature from
``__future__``, the feature is conveniently still available in Python
3 (it just does nothing).

Fixers:
    libfuturize.fixes.fix_print_with_import

#8530

The start command takes the default dbname from the path.
But when running inside a virtualenv, it is a better default to take the
dbname from the virtualenv's path.

Futurize fixers:
* lib2to3.fixes.fix_except

- As of v10, manifest files should be named `__manifest__.py`
- For backwards-compatibility, __openerp__.py manifest files
  will still be supported for the time being
- Limited refactoring, to add support for the 2 different
  naming conventions
- All textual references to __openerp_.py updated in
  documentation and examples