rfc2806bis-05 comments: parameters and telephone-subscriber

rfc2806bis-05 BNF describes an explicit ordering 
of the parameters in regards to isdn-subaddress, 
context, and param.  If this explicit ordering 
was not intended, the BNF should be changed or 
explicit text should be added to indicate that 
the above parameters are not required to be
in an explicit order.

Adding back a telephone-subscriber definition 
might help accommodate the above.  It would also 
help in correlating rfc3261's telephone-subscriber 
reference to rfc2806bis.

-brett