Double click to select all brushes of an entity.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>
Only show a texture in the UV view if exactly one face is selected.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>
Don't select siblings on double click if the clicked brush belongs to worldspawn.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>