Restlet API - core

With clear diagrams and 'responsibility-collaboration statements on the main classes/interfaces
a good exaplanation of instances,...)

1. Main design principles and benefits
   (e.g. same API for client and server logic, same API for all protocols, content negotiation on resources' representations)
2. Main classes
1. Uniform, Request and Response classes
2. Restlet class
3. Connectors
4. Routers
5. Filters
6. Components
7. Applications
8. Resources