Configuration for annotation clustering

[nbrownus]

Enable or disable clustering, on by default. Should resolve #854

[rashidkpc]

I wonder if maybe we don't want to find a way to make the granularity of the clustering configurable. The problem with turning it off completely is that drawing the markers is pretty expensive.

[nbrownus]

Fully agree that there should be a way to configure how granular clustering is, but it would also be nice to disable it entirely as well.

I can take a stab at the time based controls, which would probably look a lot like the interval config. I would likely put that in a different PR though.

[spalger]

Woops! Sorry about that! We recently replaced the master branch with Kibana 4. This action force closed all of the old pull requests against master. We will be reviewing these on a case-by-case basis and creating new tickets as necessary.

The good news is that many long requested features can be found in Kibana 4, and we're being entirely open about our roadmap. Check out the roadmap tickets (which we're still filling in) here.

If you're looking for the old Kibana 3 code you can find it here.

[w33ble]

As mentioned in #854, there's a new clustering algorithm in Kibana 4 that should fix this.