fix creation of selection campaign

fix selection campaign with default config
(cherry picked from commit d216258bc78e06fe9defb8ec26a9c383363050cd)
upgrade version
improve performances: events on DataModel are now always by batch of rows instead of individuals, so that events can handle optimization in case of several rows
fix datamodel event
data_list: be able to ask the data_list to always retrieve a field, even it is not selected by the user
grid: be able to provide a background style for every row
field_boolean: make margins smaller
applicants list: put in red the excluded applicants
some improvements when removing an organization
fix exam center: when changing room name, something has to be saved..
assign/unassign to centers
upgrade version to 0.2.7
Merge branch 'dev' of https://github.com/passerellesnumeriques/Students-Database into dev_travel

Conflicts:
	www/component/selection/selection.inc
fix documentation with custom tables