#25 clean code : no more possible to create a context on the fly when accessing notes (it was not a REST approach at all)
#25 allow the character '-' in a context name
#25 introduction of the fragment tag in the Note class and in the NoteService
#25 controller and view OK RAF : activation of link to go to the ressource linked to a note
#25 activation of link to go to the ressource linked to a note OK.
fixed #25 a notes ca be linked to a fragment tag