Merge pull request #1 from johnchase/master

added genetic drift without a bottle neck example
added new simulation
updated output
added some code from previous year's class
adding initial pieces of pairwise alignment code
adding new notebooks to toc
fixed typo
fixed typo
fixed typo
added annotation and code
Merge branch 'master' of https://github.com/gregcaporaso/An-Introduction-To-Applied-Bioinformatics

Conflicts:
	general-molecular-biology/evolution.ipynb
updates