Cleanup code

+ Corrected a bit `classes/Kohana/Cache/Sqlite.php`, to show what needs to change in the other classes
+ Replaced all 
```php
<?php defined('SYSPATH') or die('No direct script access.');
```
to
```php
<?php defined('SYSPATH') OR die('No direct script access.');
```
+ Amended PHPDoc (`classes/Kohana/Cache/Sqlite.php`)
+ Removed unnecessary comment at the end of classes, e.g.: `// End Kohana_Classname`
+ Removed trailing spaces

Please see: http://dev.kohanaframework.org/issues/4768