Refactor to use with memcached

[mangelsnc]

In view to take advantage of the new features of the memcached library (note the last 'd'), I updated this bundle and added a small suite of tests.

I have included some improvements like:

• A method to get all the registered keys from the cache
• A method to flush the cache
• A method to remove cache entries with a regular expression
• A method to enable / disable compression
• Updated setPrefix method to take advantage of the new library
• A method to set multiple values in a single call using an array of pairs key => value
• A method to remove cache entries through an array of keys

I also added a simple way to configure the bundle following the standards of Symfony2.

Any questions or suggestions are welcome!

Thanks for this bundle!

[AkshayBz]

Awesome work @mangelsnc! @beryllium - You should definitely look into this and merge it :) Might as well add CI while you are at it

[mangelsnc]

Thanks @AkshayBz !

It would be really good merging this, but I think this repo will not be maintained anymore.

@beryllium, what can say you about this? Do you need help to maintain this? Or is definitely unmaintained?

[jeremylivingston]

I would recommend integrating the php-cache bundle found here: https://github.com/php-cache/cache-bundle

It follows the PSR standard and, as you stated, this library has not been maintained for some time.

[beryllium]

~~I would say it's half-unmaintained. I recently checked to make sure it worked with Symfony 2.8, and it seemed to. Now that PSR-6 has passed, I've been considering rewriting the bundle with an eye toward A) working properly with the Symfony Config Component, B) supporting Symfony 3.0, and C) acting as a wrapper around some PSR-6 interfaces to get added support for various caching servers (while still behaving like a simple key-value store with TTL values).~~

~~One impediment to this is that I have not been working with Symfony code for a few years now, so I am not currently using this code in my own projects.~~

~~Hopefully I will find the time in the coming weeks to take a shot at the rewrite.~~

... after examing PHP-Cache, I think it would make more sense to EOL CacheBundle. There doesn't seem to be any sense in duplicating functionality in this instance.

[mangelsnc]

Anyway, this was a really helping bundle for a time, but maybe you're right and it's moment to EOL it.

Thanks for make it @beryllium, good job!