Post-release version bump to 0.2.15
Post-release version bump to 0.2.15

MathieuDuponchelle/grilo-plugins,grilofw/grilo-plugins,grilofw/grilo-plugins,GNOME/grilo-plugins,MikePetullo/grilo-plugins,MathieuDuponchelle/grilo-plugins,jasuarez/grilo-plugins,MikePetullo/grilo-plugins,MathieuDuponchelle/grilo-plugins,jasuarez/grilo-plugins,MathieuDuponchelle/grilo-plugins,MikePetullo/grilo-plugins,GNOME/grilo-plugins