Merge pull request #235 from ayr0/exposition

added figures
corrected grammar

Reverse a careless change that I made.  No more editing at 2:00am. :)
Merge pull request #236 from ayr0/corrections

corrected grammar
revised image captions in the change of basis lab.
Merge pull request #237 from insertinterestingnamehere/typos

Revised image captions in the change of basis lab.
make python style default

There is no need for a python style since all code is now Python.
The python style was leftover from the days we had two versions of the
lab manuals.
Merge pull request #238 from ayr0/styles

make python style default
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