control server to initiate additions, deletes and archivals of metricdefinitions + findSeries 'full-json' format and 'To' flag

[shanson7]

Resolves #1976

This PR is fully functional and provides:

1. Control message support for index operations: add/delete/archive defs
2. Adds a control server that is used to generate the control messages
3. Adds "full-json" format to findSeries (used by control server to resolve series to delete/archive)
4. Adds support for To param in findSeries (used to for olderThan functionality in delByTagQuery)

There are still some TODOs, and probably needs some more testing and code cleanup, but I feel it's in a place that basic design/naming/structure reviews can be being.

Note: This is rebased on #1991

[shanson7]

@Dieterbe - I know this is a lot to review. If you want, I can split it into pieces merging into a feature branch.

Logical chunking would probably be:

1. Changes for findSeries - To param and full-json format. (I might also consider adding a full-msgp format, since full-json is very large)
2. Control message types and processing
3. The control server

Let me know if you would prefer that.

[Dieterbe]

would you say that reviewing commit by commit is also a good way to split it up? if so, i can just do that.

[shanson7]

Commit by commit tells the story. It's not the cleanest, but it could work. Thanks!

[Dieterbe]

@shanson7 seems like really good work! in line with our discussions, and more than i expected (e.g. delete and archive functionality rather than just revive)

I left a bunch of comments, but nothing major.