T controller tutorial and improve documentation

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

frappy/rwhandler.py

@@ -19,12 +19,14 @@
 #   Markus Zolliker <markus.zolliker@psi.ch>
 # *****************************************************************************
 
-"""decorator class for common read_/write_ methods
+"""decorator class for common read_<param>/write_<param> methods
 
 Usage:
 
 Example 1: combined read/write for multiple parameters
 
+.. code:
+
     PID_PARAMS = ['p', 'i', 'd']
 
     @CommonReadHandler(PID_PARAMS)
@@ -41,6 +43,8 @@ Example 1: combined read/write for multiple parameters
 
 Example 2: addressable HW parameters
 
+.. code:
+
     HW_ADDR = {'p': 25, 'i': 26, 'd': 27}
 
     @ReadHandler(HW_ADDR)
@@ -197,8 +201,10 @@ class CommonWriteHandler(WriteHandler):
     calls the wrapped write method function with values as an argument.
 
     - values[pname] returns the to be written value
+
     - values['key'] returns a value taken from writeDict
       or, if not available return obj.key
+
     - values.as_tuple() returns a tuple with the items in the same order as keys
 
     """