add secondary y-axis (doesn't work properly with toggles)
refactoring: take event handlers out of drawChart function
togglable series built into google charts
remove metric checkboxes
remove old event handler
labeled logging of chart toggles
hover over pages for previews, click page numbers to visit in NB + JS refactoring
tweaked instructions
add link to guide on github wiki
code cleanup: removal of comments & unused functions
Merge pull request #169 from jenkliu/single-chart-toggle

Chart view improvements & code cleanup