DipyDoc's folder have now a 'menuname' file, read by DipyDoc::read_menu_name
(modified dipydoc.*) changed functions' names : 'init_from_xml' > 'read_from_mainfile'
added MenuNames class : the program searches every 'menu name' available in the dipydoc directory
The list of the available Dipydocs appear in the File menu
added an icon in the submenu open for all dipydoc that have been identified
(MainWindow::add_open_menu) if the number of available dipydocs is too high, all the menunames are not displayed in the submenu File>Open
Merge branch 'feature46' into dev
  Each Dipydoc folder now contains a 'menuname' file : in this file, a unique line gives the name of the Dipydoc that appear in the submenu 'File>Open'. The UI serches in the default folder all the available Dipydoc and add them to this submenu.