Deleted duplicate graph2 package
Added breadth first search (BFS) implementation for Graph
Added isConnected for Graph
comments only
Added shortest path in weighted, directed graph (a la Dijkstra)
Simplified adding of edges
Added test for unconnected graph
Added Subsets - calculates all subsets of a given set
removed commented code
Merge remote-tracking branch 'origin/master'

Conflicts:
	src/main/java/com/shaunabram/datastructures/graph/bfs/Node.java
	src/main/java/com/shaunabram/datastructures/graph/bfs/readme.txt
	src/main/java/com/shaunabram/datastructures/graph/bfs/shortestpath/Graph.java
Added BinaryTree isBalanced implementation - working but inefficient
Improved BinaryTree isBalanced implementation by caching heights
Tidied BinaryTree isBalanced implementation
moved BinarySearchTreeTest
deleted old graph classes