L2SS-622: Add an explicit per-device store for each attribute

L2SS-622: Add an explicit per-device store for all the attribute needs to know for the attribute wrapper when tied to a specific device.

Closes L2SS-622

tangostationcontrol/tangostationcontrol/clients/README.md

@@ -16,11 +16,8 @@ Inside lofar/tango/tangostationcontrol/tangostationcontrol/devices/lofar_device.
 	Init_value:		Initialisation value. If none is presents, fills the attribute with zero  data of the correct type and dimension
 	**kwargs: any other non attribute_wrapper arguments.
 NOTE: the `__init__` function contains wrappers for the unassigned read/write functions. In previous versions the read function of an RW attribute used to return the last value it had written *to* the client  instead of the value from the client. This has since been changed.  
-
-`initial_value`:
-	This function fills the attribute with a default value of all zero's with the proper dimensions and type if None is specified. 
 	
-`Set_comm_client`:
+`set_comm_client`:
 This function can be called to assign a read and write function to the attribute using the data accessor or client given to this function. The attribute wrapper assumes the client is running and has a function called ‘setup_attribute’ which will provide it with a valid read/write function. 
 
 `async_set_comm_client`:
@@ -29,14 +26,6 @@ This function can be called to assign a read and write function to the attribute
 `set_pass_func`:
 	Can be called to assign a 'fake' read/write function. This is useful as a fallback option while development is still ongoing.
 
-`_decorate_read_function`:
-Wrap an attribute read function to annotate its exceptions with our comms_annotation to be able to identify which attribute triggered the error.
-
-
-
-`_decorate_write_function`: 
-Wrap an attribute write function to annotate its exceptions with our comms_annotation to be able to identify which attribute triggered the error.
-