L3 Validation: values for NodeEditVAL.VAL_TRUE, VAL_FALSE, VAL_UNKNOWN

The values assigned for VAL_TRUE, VAL_FALSE and VAL_UNKNOWN appear to 
just follow the sequence established by VAL_WF, VAL_NS_WF, 
VAL_INCOMPLETE and VAL_SCHEMA (1, 2, 3, 4).

In scripting languages where the symbolic constants are not available, 
that would lead to code like:

if (node.canInsertBefore(node1, node2) == 6)

which isn't obvious.  It would be beneficial to change the values so 
that, at least, VAL_FALSE is 0.  I'd recommend, VAL_FALSE = 0, VAL_TRUE 
= 1 and VAL_UNKNOWN = 2.