symbols: move keysyms into LevelInfo Instead of maintaining a syms array in the GroupInfo + sym_index's in the levels. This simplifies the code somewhat. In order not to alloc for every level instead of every group, we only do it if the level has more than one keysym (with a union). Since for now this is a special case, it actually works out better memory-wise. Signed-off-by: Ran Benita <ran234@gmail.com>