Add comments and update readme

[Julesboul]

Some major refactorings in order to improve clarity:

• add comments to every classes/methods
• reorganize a bit the project (protocols, ...)
• move examples into a dedicated class ExampleOfSindarinDAP
• update the readme of the project by: describe how to use the builder, delete parts about architecture (which were moved to class comments), reorganise the part with example, ...