Merge branch 'hotfix/509'

Close #509
Merge branch 'hotfix/509' into develop

Forward port #509
[2.0.4] Set version

- Set release version to 2.0.4
Merge branch 'release/2.0.4'
Update docs/languages/es/user-guide/database-and-models.rst
Deleted articles that are not exists in the English documentation
translate Zend\Db\Adapter
Restore some of used files

Restore zend.pdf.*, zend.search.*, zend.service.*
Rename restored files: remove dot after 'zend'
Translate Zend\\Db\\Metadata
Add En-Revision
Translate Zend\Db\ResultSet
Translate Zend\\Db\\RowGateway
Fix line length
Translate Zend\\Db\\Sql
grammar mistakes corrected
Translate Zend\\Db\\TableGateway
Add doc for new Zend\Test component
Fix display bugs
Add zend\test in index
Refac zend\test doc folder archi