[osis-core] xml:lang

[Todd Tillinghast]

Hmmm.

xml:lang and <language> serve different purposes.  I would not expect
anyone to use the <language> element to determine which language the
characters in children elements should be interpreted as.

Because within the same context there will likely be OSIS document
encoded in different languages, when none is specified there is no
reasonable basis to establish a default when none is specified.  I think
this is reason enough to require a xml:lang on <osisText>.

Todd