implement path node list to movement for slime

[perryBunn]

basic psudocode of the path following

        if path is not null then
          if self x and y are within range of last node in path then
            -- use the original path code below
          end
          target = node(current)
          if distance to taget node is less than some range then
            change target node to current
            change target node to next node in array
            if target node is greater than path length then
              subtract one
            end
          end
          -- path to node similar to original code
        end