all: rename parameters to accessibles in module classes

+ make accesses to <module>.parameters work again

Change-Id: I91c09b0f9f5f28d78cd644f83a96c8772e5977e5
Reviewed-on: https://forge.frm2.tum.de/review/20249
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Tested-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>

secop_demo/test.py

@@ -54,7 +54,7 @@ class Heater(Drivable):
     class name indicates it to be some heating element,
     but the implementation may do anything
     """
-    parameters = {
+    accessibles = {
         'maxheaterpower': Parameter('maximum allowed heater power',
                                 datatype=FloatRange(0, 100), unit='W',
                                 ),
@@ -73,7 +73,7 @@ class Temp(Drivable):
     class name indicates it to be some temperature controller,
     but the implementation may do anything
     """
-    parameters = {
+    accessibles = {
         'sensor': Parameter(
             "Sensor number or calibration id",
             datatype=StringType(