Bug fix. Sometimes the control buttons from a previous running project where shown if a user opened another project without killing the application.

Signed-off-by: Michalis Vitos <info@michalisvitos.gr>
XML diagram added to documentation

Signed-off-by: Julia <julia.altenbuchner.11@ucl.ac.uk>
Merge branch 'master' of https://github.com/ExCiteS/Sapelli
transport_XML example added
Added a bit more information + contributor names
Merge branch 'master' into lib2x+