please fix labels on graphs with wildcards

[kellyjmk]

In lib/models/graph.rb it looks like maybe this is a work in progress:
# fixme proper labeling... maybe
# technically we do know, so this can be fixed

My use case is that I want to graph the top ten tables by insert. My metrics looks like cluster1.host1.table1.insert_count and I want to graph highestAverage(cluster1.host1.*.insert_count, 10) but the legend doesn't tell me what those top ten tables are.

Thanks!