- rename class to ColumnSchemaBuilder as this is more appropriate
- changed internal organisation to match how the rest of schema related classes work
- the ColumnSchemaBuilder is now created the same way as QueryBuilder is
- removed static call magic and method annotations, now real methods are called as they are
- the whole code works on objects in a db context now instead of setting database connection in global state
- trait is now used by Migration by default but can be used in other contexts as well
Migration usage is now as follows:
```php
$this->createTable('example_table', [
'id' => $this->primaryKey(),
'name' => $this->string(64)->notNull(),
'type' => $this->integer()->notNull()->defaultValue(10),
'description' => $this->text(),
'rule_name' => $this->string(64),
'data' => $this->text(),
'created_at' => $this->datetime()->notNull(),
'updated_at' => $this->datetime(),
]);
```
there is no reliable way to determine the cubrid PDO extension version used
and also no reliable way to detect which combination of server and client produces wrong behavior.
By requiering 9.3 or higher in both client and server we can be sure it works.
fixes#852