Version identifier

It was discussed at the Mozilla-hosted meeting that a version identifier,
to help developers identify what appcache was in use, would be helpful.  I
wanted to make a simple proposal for that: a version token in the SETTINGS
section.  This would be the token "version" followed by a single simple
token string (not necessarily numeric; up to the developer what they
actually put in there), e.g.:

SETTINGS
version 1.0

this would then be exposed this on the applicationCache object:

readonly attribute DOMString version;

Thoughts?

-Chris