SimpleDirectedGraph: added ConnectionsIterator, added setEnd to Edge,
made not final "item" in Vertice, refactored connect, connectAndGet,
added getNewEdge(int,int), implemented getConnections
TestSimpleDirectedGraph: removed testGetConnections, changed
testConnect: changed NoSuchElementException to IllegalArgumentException
TestItem: added
TestSimpleDirectedGraph: replaced Item with TestItem
TestItem: added static getNewTestArray, made contructor private
TestSimpleDirectedGraph: changed initialization of final array items to
TestItem.getNewArray call
TestSimpleDirectedGraphGetConnections: added
TestSimpleDirectedGraphGetConnections: added field first, added
getConnectionsOfFirst, implemented testHasNext
TestSimpleDirectedGraphGetConnections: combined testHasNext and
testNextIndex to testHasNextAndIndex (same of previous), implemented
testNext, testHasNextAndIndex, testPrevious, testHasPreviousAndIndex
TestSimpleDirectedGraphGetConnections: added connectFirstWithAll,
getToEnd(iterator), canRemoveFrom(iterator), implemented testRemove
TestSimpleDirectedGraphGetConnections: implemented testSet, added
canSet(iterator)
SimpleDirectedGraph: fixed ConnectionsIterator.set
SimpleDirectedGraph: made field "item" final in Vertice
TestSimpleDirectedGraphGetConnections: implemented testAdd