Fixed sorting by type/owner
Fixed sorting by type/owner

Fixes https://github.com/lxde/pcmanfm-qt/issues/459.

Previously, when files were sorted by their types/owners, they were shown irregularly within each group. With this patch, they're sorted by their display names within groups.

The patch is thorough and does the same thing for all sortings, except for sorting by names.

lxde/libfm-qt,lxde/libfm-qt