Added ymin option to timeseries graph.

Support option to set ymin. It'll grab ymin from the data if this
option is not set.
fix json request and add title in discovery mode
Merge pull request #47 from trbs/master

fix json request and add title in discovery mode
Merge pull request #45 from drspin/feature/timeseries_ymin

Added ymin option to timeseries graph.