user: display additional stats

* Compute various stats and display them in the user profile
* Extract the drawStats function to graph.js.erb, since it is quite generic
* Update drawStats to add some room at the top of the series

Signed-off-by: diditclear <didyourupgradeclear@gmail.com>
legs: prettify _simple_legs_table graph

* Switch back to the bar graph, which seems simpler to understand than scatter plots
* Add some room at the top

Signed-off-by: diditclear <didyourupgradeclear@gmail.com>
stats: various fixes

* Add titles to pages
* Fix UA specific defaults

Signed-off-by: diditclear <didyourupgradeclear@gmail.com>