Adding Creative Common By-NC License

  - Taken from http://creativecommons.org/licenses/by-nc/3.0/
Adding trailing "/" to permalink

  - Without the slash, it becomes a download not a webpage
Wrapping at 80 Characters

  - Overflow issue on the jekyll side
Adding Creative Commons By-SA

  - Taken from http://creativecommons.org/licenses/by-sa/3.0/
Merge branch 'gh-pages' of https://github.com/jmburges/choosealicense.com into gh-pages