Issue #70

Here is the revised text making the relationship of the status value
attribute to the reason codes explicit.  

Element <Status>


The <status> element specifies the status of a KeyBinding instance.

The status value MAY be supplemented with codes that state the status of
specific aspects of the key binding status that were validated.

The <Status> element contains the following elements and attribute:

<ValidReason>  [Any Number]
A status aspect that was evaluated and found to be Valid.
<IndeterminateReason>  [Any Number]
A status aspect that could not be evaluated or was evaluated and returned an
Indeterminate result.
<InvalidReason>  [Any Number]
A status aspect that was evaluated and found to be Invalid.
StatusValue [Optional]
The key binding status

The enumerated type AssertionStatus is used to indicate the key binding
status. The following values are defined:

xkms:Valid
The key binding is definitively valid.
xkms:Indeterminate
The status of the key binding cannot be determined.
xkms:Invalid
The key binding is definitively invalid.

If reason codes are specified  StatusValue attribute MUST be consistent with
the reason codes specified as follows:

*	If an <InvalidReason> code is present the StatusValue attibute MUST
have the value xkms:Invalid
*	If an <IndeterminateReason> code is present the StatusValue attibute
MUST have the either the value xkms:Indeterminate or the value xkms:Invalid.
*	If neither an <InvalidReason> nor an <IndeterminateReason> code is
present the StatusValue attibute MAY have any defined value, i.e.
xkms:Valid, xkms:Indeterminate or xkms:Invalid.

The following schema defines the <Status> element and StatusType and
AssertionType types: