Small layout change
Retrieve the list of dates grouped by user during an election

And return this list as part of the stats dictionary so that the UI can
do something with it
Count for each day of the election how many people voted

Store the result in evolution_data and the list of days in evolution_lbl
These can then be used to plot the evolution of the number of voters
during the election.
Import the jquery flot library used to make plots in the result page
Show in the result page the evolution of the number of voters during the election
Include the last day of the election in the days checked for the plot
Add a mention that there is more info when hovering over a bar of the graph
Include the timestamp in the group_by to make pg happy - thanks faitout
Activate the profiler with --profile
Rename evolution_lbl to evolution_label as per @ralphbean 's advice
Adjust label in the graph as per @ralphbean 's suggestion
Rename stats['dates'] to stats['vote_timestamps'] as per @ralphbean 's advice
Merge pull request #40 from fedora-infra/evo_graph

Graph: evolution of the voters on the result page