Tally computation uses weight for voter groups. When computing the vote of each voter, the vote is multiplied as many times as the value of the weight.
If computation is done in the backgroud, by calling tasks.election_compute_tally.delay(), the weights seem to be ignored. No idea why for the moment!
Thus, computation is not done in the backgroud now (by not using .delay in calling the function).
In the voting booth, selection of voter group appears with more evidence in the begining.
An empty option of voter group is selected by default, and not selecting any group causes a message to be displayed (asking the user to select some option).
Merge branch 'master' of https://github.com/kaiokaram/helios-server

Conflicts:
	helios/views.py