This commit adds Nihon Route 49. It has everything necessary to work, but the wild Pokemon don't seem to spawn. I've added infrastructure that should allow this to happen, and it works for Kanto, so I am presuming that some other tomfoolery is at work.
I've also added Folage and Barreau, and implemented Folage into the Headbutt Tree table. This was to give them to the Bug Catcher on the route.
This fully adds Cliff Cave itself. The rest of the route isn't there, but you can access the cave via the Debug Room, featuring a crudely made cave structure.
I've also modified the Rock Smash wild data to feature some additional Pokemon. The Beach has a 20% Corsola, and Dark Cave has a 20% Phanpy, among other bits. Level scaling has also been applied.
The Cliff Cave music isn't right, I believe...but I don't know what it's actually meant to use, I haven't played HGSS since it was current gen.