IOManager should provide the number of stations
This would allow end user applications to properly allocate memory (in case of a vector aimed at containing all stations) instead of naively relying on vecMeteo[0].size() to provide the proper number of stations.
This means that IOManager could return the number of stations' keys in io.ini (for plugins that list each station) or ask the plugin itself to return this number of station. => in any case, the plugin would have to return it (only the plugin knows if the content of io.ini is enough).
Could we end up in a situation where the plugin does not even know in advance how many stations it would encounter?