Box-volume ipynb example

[pgkirsch]

Added new box volume ipynb example Re. issue #42

[bqpd]

I'm going to wait to merge this until the latex printing of alpha and beta work; either through #72, #68 etc or through just adding to the lookup table in nomials.py

[bqpd]

See the notebook file here

[whoburg]

Sweet!!

@bqpd, is there a better way to print the solution, so we don't have new users copying all that printing code?

[bqpd]

I just print the data dictionary myself (print gp.solve()), but I could fold this pretty-printing code into the gp class...