Feature 137 - mongoose history

Added ability to use mongoose history (https://github.com/rossan/mongoose-history).  There is an option named saveHistory that defaults to false meaning no history will be saved on the list.  There are a few concerns i have and they are as follows:

1. I had to fork mongoose-history and add a fix to the project which was miniscule, so instead of using npm repo I use my on github account within the package.json

2. I added a conditional statement in list.js within the constructor to check if option saveHistory === true then use mongoose-history plugin for that list, however, there probably is a more elegant way to accomplish this same task, but I could not find where you enforce options on the list.

I also updated the docs with the new option