In one weird case (suunto), the code in libdivecomputer.c
generates a device node directly instead of going the usual
way (setting the data in the dc-structure of the imported
dive). It is unclear to me whether that has to be that way,
as it depends on the chronological order of callbacks to
event_cb() and dive_cb().
Therefore add a device_table pointer to device_data_t
so that the downloader can add the device to this table. This
only adds the pointer, but does not yet use it in the
downloading code.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>