Changed default MySQL table collation to utf8_unicode_ci

Default table collation changed to `utf8_unicode_ci`, as it handles properly a much wider array of characters (Cyrillic, for example) at a generally negligible cost of performance.

lib/Doctrine/DBAL/Platforms/MySqlPlatform.php

@@ -376,7 +376,7 @@ class MySqlPlatform extends AbstractPlatform
         }
 
         if ( ! isset($options['collate'])) {
-            $options['collate'] = 'utf8_general_ci';
+            $options['collate'] = 'utf8_unicode_ci';
         }
 
         $query .= 'DEFAULT CHARACTER SET ' . $options['charset'];