It is a somewhat fragile thing to do.

Fix PSR2 rules : "As per PSR2, the static declaration should come after the visibility declaration."

 Closes #2436

fixes #2270

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.

Support for Partial Indexes was available in Doctrine 1 following
http://www.doctrine-project.org/jira/browse/DC-82. This commit
reintroduce support for Doctrine 2. We use the same syntax with an
optionnal "where" attribute for Index and UniqueConstraint.

See symfony/symfony#10238

This reverts commit 5a46f577.