use the more idiomatic way of checking if association is empty
renamed install_status_chart partial to pie_chart as it is more intention-revealing
refactored charts. preparing for machine database charts
pushing forward on database size graphs
completed filled line graph for database sizes
Added overlays for stream count and content item count
Added datum growth over time charts
removed cache override that prevented results from being cached
stack database size lines
Compute correct value for tooltip
Merge pull request #4 from snowmoonsoftware/dbstats

Implement database size charts