upd the interface to read/write multiple private/public packets.

{VirtualStrip}.bass/mid/treble implemented reading from public packet NBS=1

vban_cmd/enums.py

@@ -0,0 +1,15 @@
+from enum import IntEnum
+
+
+class NBS(IntEnum):
+    zero = 0
+    one = 1
+
+
+BusModes = IntEnum(
+    'BusModes',
+    'normal amix bmix repeat composite tvmix upmix21 upmix41 upmix61 centeronly lfeonly rearonly',
+    start=0,
+)
+
+EQGains = IntEnum('EQGains', 'bass mid treble', start=0)