[participants] Update participants counter and balloons after voting. Closes #406.
[sidebar] Update participants counter when vote. Closes #406.
[participants] Improved pluralization. Related to #406.
Merge branch 'development' into 406-update-participants

Conflicts:
	lib/participants-box/view.js
Merge pull request #499 from DemocracyOS/406-update-participants

406 Update participants