WIP multiple data sources per graph
data, title, and legend all know how to use multiple data sources
Fix for data servers that have differently-spaced samples. Also data server in legend
Fixes legend display for multi-source graphs
Removes an extra console.log
Comments about NO_DATA_FOR_TIMESTAMP
Fixes annotations to work with one data server.

I broke annotations by not updating them to reflect the new ways data is
retrieved (bad fhats!). This is a shim to make annotations work with one
data server; more work will be required to allow annotations to work with
all data servers in the graph.
Fix annotations retrieval
Fix for legends on graphs with custom titles
I'm bad at legends
Configurable legend lengths
options_ isn't always these
Finally removes the one-ds-per-graph warning
Merge pull request #53 from fhats/7_multi_ds

Gives Firefly the ability to have graphs with stats from multiple data sources