Update some header files (#373)

Also moved a lot of extern variable declarations into the
 their appropriate header file(s)

Signed-off-by: Taggerung <tyler.taggerung@email.com>

include/functions.h

@@ -13,8 +13,6 @@ void func_8000F628(void);
 void func_8006B7E4(Player* player, s32 arg1);
 void func_800267AC(Player* player, s8 arg1, s8 arg2);
 void func_8005D290(void);
-// TODO: should rot, arg4, and arg5 be rotx, roty, and rotz?
-void camera_init(f32 x, f32 y, f32 z, s16 rot, u32 arg4, s32 arg5);