FAQ: Introduce a new subsection, explain why TSD returns too much data.

Change-Id: I4315e6d0348bf0479a9aeb9aecedc164b44f729c
FAQ: Edit / clarify a couple minor points.

Change-Id: Ie866610f08a547a231575ae6a5740cb504dff41f
We're in 2013 now.

Change-Id: Ibb0289c57cff7c72b776c0df1d27f6d708b8d612
Add some documentation on how OpenTSDB queries are processed.

Change-Id: Ie259b6b0a8265ab716691f57ca9d2a96a782d7d5