The PDO connection allow the instantiation of the connection even if the dbname
parameter isn't present. This change is there to make sure both behave the same way.

Fixes the warning emitted by mysqli when sqlstate is not set (yet?).
http://git.php.net/?p=php-src.git;a=blob;f=ext/mysqli/mysqli_prop.c;h=2d36336372b75922bd8fbf40c5c9054a5230c8a0;hb=HEAD#l36

Warning masks actual connection error.

Added flags support for mysqli::real_connect in Mysqli driver. This is necessary if you want to set connection options like compression or SSL encryption.

 * license
 * author tags
 * doc blocks
 * new lines

This PR introduces a new PingableConnection interface and exposes
a ping method on \Doctrine\DBAL\Connection. For drivers where no
ping is supported, a \Doctrine\DBAL\ConnectionException is thrown.

 * push error handling down to when it occurs
 * WIP, as I am unable to trigger false currently

 * move supportedDriverOptions into setDriverOptions
 * make setDriverOptions private
 * support \MYSQLI_SERVER_PUBLIC_KEY on 5.5.0+

 * fix typo
 * remove fluent interface

 * introduced $_supportedDriverOptions to validate what is passed into the object
 * added `setDrivrOptions()` which sets the array and throws exceptions

- Fixed docblocks
- Removed return statements on void methods
- Cleaned up unused private / local variables
- Fixed license issues
- Removed SVN leftovers
- Fixed doctrine-project.org links
- Added line breaks before return statements