Add jobs

[matthew-parlette]

We need to add jobs to the game.

This will consist of a few things:

1. Add a Job class to store the job variables
2. Add a jobs list to the Location class
3. Add a jobs section to the map.json
4. Add a link to the jobs in the location dictionary in map.json
5. Modify the Map class to read the new json elements
6. Add a job variable to the Player class