Client: fix lot of bug into the coverage graph

Link: https://github.com/sebhtml/Ray-Cloud-Browser/issues/40
Link: https://github.com/sebhtml/Ray-Cloud-Browser/issues/41
Link: https://github.com/sebhtml/Ray-Cloud-Browser/issues/42
Signed-off-by: Jean-François Erdelyi <jean-francois.erdelyi.1@ulaval.ca>
Reviewed-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>