Updated documentation, added examples

Dave,

I stepped through the code and did a quick example of training and predicting with all of the defaults.

Below are my comments and questions:

1. What was the thinking behind using the argument parser and making the default way of using the program to be to execute the program through the command line? I think it would be easier to have helper functions that allow the user to easily import the modules and execute the functions in their own code, without having to use the sub processes library or executing through the command line.

Let me know if you want me to modify the code to do this.

2. I created an examples folder. I put in one example using all of the default options. I will play with this some more later this weekend.

3. I think it would be nice to have the DB_FILE be an optional argument. I think the default could be to just create a db using some name that is located in the working directory. I tried to do this, but ran into issues. I will attempt this again later this week.

4. In the documentation, all of the arguments were listed under "Optional Arguments". However, it seems that DB_FILE and DATA_FILE are required arguments. I updated the documentation to reflect this.

5. I altered the wording in the documentation for the arguments DB_FILE and DATA_FILE to wording that I think users will find more intuitive. For example, it took me a few tries and stepping through the code to figure out that DB_FILE wasn't a database that I actually needed to provide, rather the user just needs to specific a name and the code will create the database.

Things I still want to do:

1. Create more examples and use more options than just the defaults
2. Create a way for a  user to import the code as a module and execute the code without having to use the shell
3. Create some unit tests to validate the functionality
4. Add some standard graphics output


Let me know your thoughts!

Adam