Support data parameters in R interface

[Sean Kauffman]

Right now the R interface only supports timestamp/name and no data parameters. Add support to the API. Like the current API, it should work with dataframes.

Since no one is using the R interface (afaik), this is a minor priority.

[Sean Kauffman]

Update the R interface to take data. This is a bit of a long time coming. Mostly fixes issue #8. Still doesn't output maps.

→ <<cset 250b7a0f3777>>