Support OCI8 statements crossing transactions [DBAL-202]

Fix Statement class passing bound objects to SQL logger

[DBAL-249] result cache with fetch type PDO::FETCH_COLUMN

[Mysql Platform] Added mapping for binary and varbinary.

[mysqli] Added support for fetchAll(PDO::fetch_column)

[mysqli] Added mysqli driver to travis tests.

Fix Statement class passing bound parameter objects to SQL logger without type information: save parameter's converted value

PHPDoc blocks improvments + 1 CS Fix

[DBAL-166] Default MySQL to UTF8/utf8_general_ci. Allow to set default table options from SchemaConfig.