General functionality.

1. Implemented a moveable Camera class.
2. World class now has vectors which contain the circs.
3. up_ property added to the Media class which tells whether SDL has quit or not.
4. WorldInit now holds all information needed to create a world (including height and width).
5. WorldInit split into decl and impl.
6. Basic rendering was implemented.
7. Started versioning (v0.1.1).
8. Keys map added to the Media class.
9. Food and Stub classes added.