Remove not needed stuff from the PHPUnit boostrap file

Close #662

Support for Partial Indexes for PostgreSql and Sqlite

DBAL-669 - Update SQL generated by the schema tool will also create schemas

Updating a schema should introduce also schema creation statements in the generated SQL

Fix rst list

The current version is not displayed correctly at
http://docs.doctrine-project.org/projects/doctrine-dbal/en/latest/reference/portability.html

Improve QueryBuilder docs

* Remove aliases from examples where they make no sense
* Fixed copy paste error

While technically it could work, the schema introspection of Sqlite
platform has severe flaws preventing us to provide reliable support
of partial (and non-partial) indexes for the moment.

Update docs to include warning when using object type with PostgreSQL

Update docs to relfect the changes to QueryBuilder::from made in #646

Make the $alias parameter in the `from` method optional

Split the methods in TestUtil more and improve naming

foreach AS -> foreach as