add tutorial for Berlin hands-on workshop
+ improve the documentation (hints for structure welcome)
+ remove 'optional' parameter property
(is not yet used - should not appear in doc)
+ added test property in frappy_demo.cryo alters Parameter class
('test' property appears in Parameter doc)
Change-Id: I3ea08f955a92f72451fd23a5ff00d1185c7fb00e
