no more None keys in selection
tooltip modification in line graph
fixed none type only in dict and perfstore date return type
defining more accurately when an event already exists
better behavior for graphes point shapes
upsert instead of insert in cstorage for new events
Merge branch 'develop' into no-redis

Conflicts:
	sources/canolibs/lib/canolibs/cstorage.py
	sources/externals