Fix some marginal bugs, and the version of [AV]faces.

- Bump version of [AV]faces to 2.2.
- With very bad luck, some channel numbers could overflow the range of an integer due to float rounding, and produce DEBUG_CHANNEL or PUBLIC_CHANNEL as output.
- If both CHANGED_INVENTORY and CHANGED_LINK came at the same time, [AV]prop would fail to handle both.
- There was code that did nothing in [AV]faces. While it caused no bug per se, if it was reused in future then it could be affected by the same problem as that in [AV]prop.

AVsitter2/[AV]sitB.lsl

@@ -524,7 +524,7 @@ default
                 CONTROLLER = MY_SITTER = id;
                 menu_page = 0;
                 current_menu = -1;
-                menu_channel = ((integer)llFrand(2147483646) + 1) * -1;
+                menu_channel = ((integer)llFrand(0x7FFFFF80) + 1) * -1; // 7FFFFF80 = max float < 2^31
                 llListenRemove(menu_handle);
             }
             else if (num == 90065 && sender == llGetLinkNumber())