SimpleCity: added index
SimpleNode: changed ArrayList of children to LinkedList
SalesmanAlgo: added printTree, recurseParent, addChildren,
changeCacheCurrent, CityNode.toString - implemented loop
SalesmanAlgo: changed algorithm from constructing new tree and switching
every time to just modifying one tree
SalesmanAlgo: added int[] to CityNode
renamed Node to LinkedNode
LinkedNode: added getFirstChild, getFirst, getLast
SimpleNode: added empty methods
LinkedNode: removed getChildren, added addBeforeLast, addAfterFirst
SimpleNode: implemented getFirst, getLast, getFirstChild, addAfterFirst,
addBeforeLast
reverted to fb337966