Lab: Data Structures

Lab to review different kinds of datastructures.
hash table explanation and solution

Explain hashtables and implemented a simple hashtable with chaining for
collision resolution.
explain binary search trees
begin section on graphs
begin section on graph data structures
begin section of DFS and BFS

Discuss depth first search and breadth first search
explain DFS and BFS using two examples
solutions for graph search problems
remove section on balanced binary trees

Removed because I think will go over the time constraints of a lab.
solution for binary tree
clarify some sentences and fix spacing
Merge pull request #241 from ayr0/datastruct

Lab: Data Structures