implemented command to get rid of the "Cache/update.php" and template-files

This PR fixes an issue with the non-PSR0 compliant way the `LoggingMemcacheTemplate.php` and `MemcacheInterfaceTemplate.php` are named. Under certain circumstances (in conjunction with `--optimize-autoloader` ?) this causes `composer` to generate an incorrect classmap where the class `LoggingMemcache` points to  `LoggingMemcacheTemplate.php` (which will break everything).

What I did
* wrapped the `update.php` into a Symfony-Command
* moved the `Cache/LoggingMemcacheTemplate.php` and `Cache/MemcacheInterfaceTemplate.php` to `Resources/codegen/LoggingMemcacheTemplate.php` and `Resources/codegen/MemcacheInterfaceTemplate.php`