merge diffusions and episode, work on different fixes, duration are timefield, make it work

aircox_programs/utils.py

@@ -1,6 +1,23 @@
+import datetime
+
+def to_timedelta (time):
+    """
+    Transform a datetime or a time instance to a timedelta,
+    only using time info
+    """
+    return datetime.timedelta(
+        hours = time.hour,
+        minutes = time.minute,
+        seconds = time.seconds
+    )
+
+
+def seconds_to_time (seconds):
+    """
+    Seconds to datetime.time
+    """
+    minutes, seconds = divmod(seconds, 60)
+    hours, minutes = divmod(minutes, 60)
+    return datetime.time(hour = hours, minute = minutes, second = seconds)
 
-def ensure_list (value):
-    if type(value) in (list, set, tuple):
-        return value
-    return [value]