Annotate source code

[adi64]

We should annotate and comment our source - not only so we can get a better understanding but also so that we can autogenerate a doxygen documentation.

[Fidge123]

We should agree on a documentation style. We can write using

• 1st person explain as if the class is talking ("I provide this functionality")
• 2nd person as if we are explaining it to the user ("You can use this")
• 3rd person describing the class in an abstract way ("This class provides functionality").

[NaskyD]

I prefer the 3rd person style