Added IBlobPersistor with untested dummy implementation based on file system. (Keep S3 one outside to avoid dependencies. Probably later will add Fredis.AWS with interfaces implementations for S3, DynamoDB, SQS, Redshift - but only if I will need them myself)

TODO: Test blobs. Then migrate cache stuff here. What a mess I have done with that... the problem is not that Redis clients are bad or we could do a automagical combination of cache and persistence... The bigger problem is sane conventions about keys namespaces and typed convenient access to operations other than entire POCOs PUT/GET. I just do not want to think about Redis keys and commands and binary zipped serialization.

Also need to decide about Memcached - if it stays, then many convenient operations from above will require one more interface, like ICache and IAdvancedCache. Given the same AWS pricing and upcoming Redis cluster release and its likely ubiquitous adoption - better to forget about Memcached (and one more dependency)

What about Redis sharding similar to DB? Main big node for the very best Redis features while shards are for IDataObjects and related objects, instead of Memcached and on steroids...