add gain,levels

implement gain, levels for strip/bus classes.

add to readme

vban_cmd/bus.py

@@ -71,8 +71,21 @@ class OutputBus(Channel):
             raise VMCMDErrors('label is a string parameter')
         self.setter('Label', val)
 
+    @property
     def gain(self):
-        return self.public_packet.busgain[self.index]
+        def fget():
+            val = self.public_packet.busgain[self.index]
+            if val < 10000:
+                return -val
+            elif val == ((1 << 16) - 1):
+                return 0
+            else:
+                return ((1 << 16) - 1) - val
+        return round((fget() * 0.01), 1)
+
+    @gain.setter
+    def gain(self, val: float):
+        self.setter('gain', val)
 
 
 class PhysicalOutputBus(OutputBus):
@@ -96,11 +109,12 @@ class BusLevel(OutputBus):
 
     def getter_level(self, mode=None):
         def fget(i, data):
-            return data.outputlevels[i]
+            val = data.outputlevels[i]
+            return -val * 0.01
 
         range_ = self.level_map[self.index]
         data = self.public_packet
-        levels = tuple(fget(i, data) for i in range(*range_))
+        levels = tuple(round(fget(i, data), 1) for i in range(*range_))
         return levels
 
     @property