Add redis cache support

[titanrat]

Add redis cache support using MemCache type as example

[PowerKiKi]

Thanks for the contribution. You can fix the code style via ./vendor/bin/php-cs-fixer fix.

However there are talk to refactor entirely the caching system in #3 (and also a PR for Redis against PHPExcel). Please join in the discussion and make your opinion known whether PSR-16 support would be an interesting feature. I'll wait until we reach a agreement with @MarkBaker on the cache system future to merge or reject this PR...

[titanrat]

Code style fixed. I'll try to join discussion later.

[Quix0r]

I would like to see use (which is like impot in Java) instead of having static (full-qualified) class references everywhere:

use \Vendor\Project\Type\Foo;

$foo = new Foo();

Now if \Vendor\Project\Type\Foo has changed to e.g. \Vendor\Project\Type\Fooier\Foo then you have to update all references, with use only in the header in each file.

Edit: I opened an issue for this.

[titanrat]

@Quix0r You want me to fix that in my new file CachedObjectStorage\Redis.php ?

[Quix0r]

@titanrat I'm no dev here, maybe @PowerKiKi or @MarkBaker can say something about it?

[titanrat]

@Quix0r fixed. But only in file which i created.

[Quix0r]

Looks fine with me.

[Quix0r]

@titanrat fine with me. :-) And maybe the people here won't like your PR then.

[titanrat]

@Quix0r Let's see what they say.

[PowerKiKi]

@Quix0r like I said earlier, I won't merge this until we get a decision in #3 about moving to PSR-16. There are chances that this PR will become useless.

[PowerKiKi]

This made obsolete by the introduction of PSR-16, thanks for the contribution anyway.