[Gexiv2] Bug for south hemisphere

[Emmanuel Christophe <emmanuel christophe gmail com>]

Hi all,

Latitudes in the south hemisphere are not correctly interpreted
by gexiv2_metadata_get_gps_latitude.
In the file gexiv2-metadata-gps.cpp, more exactly here:
http://redmine.yorba.org/projects/gexiv2/repository/revisions/master/entry/gexiv2/gexiv2-metadata-gps.cpp#L132
the sign should be reversed if latitude_ref[0] == 'S' (not 'W')

Emmanuel