Drones updates

Markdown sections put together, some small readability changes in code.

This lab is done together with the students - discussing the references, what should they look like and how should they be put in the command vector, and then doing the state feedback. The way the code is given right now is assuming there are no velocity sensors, is it ok to leave it like that? Also, there are some initialisations for the integrator part, which i guess can be changed to make it applicable with the simple sum method.