Technical documentation

[jkemperman]

The current state of the technical documentation is not good enough. According to the documents on n@tschool, we need the following:

• Class diagram showing architecture (current one is out of date and incomplete)
• Technical choices, motivation and consequences (out of date and incomplete as well)
• Algorithms used and implementation details (same here)
• Are there any features that are not implemented or incomplete? (Don't think there are. If we end up not finishing something we'll have to add it in here.)

[jkemperman]

This issue is splitted up in several smaller ones.