Add a new Model, it's the QSortFilterProxyModel that accepts
functions to filter / sort. so instead of creating a new class
for each different sorting (overkill), now we can just create
a function and pass to this class. I'll rework the filtering
system of subsurface to use this - in the meantime I've created
this to ease the creation of another filter: the dive sites
by gps coordinates.
Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
ab32295f89