[ADD] GGbr_corners_v8

[Synnthetik]

Take cornered and give it an upstairs walkway on both sides of center wall with ladders and bridges to the upper walkway around the outside. All the fun of cornered with some extra paths adding a vertical dimension to the map.

d/l available at:

https://gamebanana.com/maps/133821

[hippo]

YES another one! =D