Column data store

In a meantime elliptics got column store support.
It is implemented in eblob only though, filesystem backend does not support this feature.

I’m thinking about proper API for this feature though.
There are million of changes in the current tree, we will polish it and release new version very soon, which will draw the line between current rapid development cycles with extreme feature creation rate and steady maintenance support. Probably :)

Stay tuned, I will make new post, when things are ready for prime use.