rework Epics support/testing with LS336

second approach, better fitting what was agreed upon so far.
- pv_names are local to SEC-node, so not exporting via json and marking
  them 'private'
- 2 devices for 2 temperature control loops, not one 'monster' device
  which handles everything.
- read_status implemented
- write_target also updates the status (may be sensible to go to the core?)
- provide working stubs in case epics is not installed (-> testing possible)
- tested with the stubs.
- tests with real epics.

found problems:
in EpicsTempCtrl(EpicsDriveable) the read/write_<paramname> methods from
EpicsDriveable needed to be reimplemented. This should not be needed!

Change-Id: I9e4eeaff83114131d117c8f04fba758dfe22237b

etc/cryo.cfg

@@ -1,5 +1,9 @@
 [equipment]
+# set SEC-node properties
 id=cryo_7
+description = short description
+	
+	This is a very long description providing all the glory details in all the glory details about the stuff we are describing
 
 [interface tcp]
 interface=tcp

etc/epics.cfg

@@ -1,11 +1,59 @@
-[server]
-bindto=0.0.0.0
-bindport=10767
+[equipment]
+id=see_demo_equipment
+
+[client]
+connectto=0.0.0.0
+port=10767
 interface = tcp
 framing=eol
 encoding=text
 
-[device epicspv]
-class=devices.epics.EPICS_PV
-sensor="test_sensor"
-max_rpm="very high"
+[interface testing]
+interface=tcp
+bindto=0.0.0.0
+bindport=10767
+# protocol to use for this interface
+framing=eol
+encoding=demo
+
+[device tc1]
+class=devices.demo.CoilTemp
+sensor="X34598T7"
+
+[device tc2]
+class=devices.demo.CoilTemp
+sensor="X39284Q8'
+
+
+[device sensor1]
+class=devices.epics.EpicsReadable
+epics_version="v4"
+.group="Lakeshore336"
+value_pv="DEV:KRDG1"
+
+
+[device loop1]
+class=devices.epics.EpicsTempCtrl
+epics_version="v4"
+.group="Lakeshore336"
+
+value_pv="DEV:KRDG1"
+target_pv="DEV:SETP_S1"
+heaterrange_pv="DEV:RANGE_S1"
+
+
+[device sensor2]
+class=devices.epics.EpicsReadable
+epics_version="v4"
+.group="Lakeshore336"
+value_pv="DEV:KRDG2"
+
+
+[device loop2]
+class=devices.epics.EpicsTempCtrl
+epics_version="v4"
+.group="Lakeshore336"
+
+value_pv="DEV:KRDG2"
+target_pv="DEV:SETP_S2"
+heaterrange_pv="DEV:RANGE_S2"