[Dev] Differentiate 0 and no values

[BRaimbault]

No description provided.

[idrissait]

Was done, has it been updated on the core?

[BRaimbault]

I think we discussed it but it hasn't been properly addressed.

[heidieh]

Currently 0 and null(no entry) are not distinguished from each other. In my understanding:
To resolve this issue properly requires a restructuring of the data records. Currently, each data record contains an entry for cases AND an entry for deaths. So for any given chart, a 'bin' will be created for that record with a 'starting point' of 0 for both Cases and Deaths. So for example, if 5 Cases exist for a given record but Deaths were not recorded, then Deaths will default to a value of 0.
In the current composite line series, an option is set to display 0s but not nulls, however there seems to be a bug with this.