draft-ietf-sming-01.txt hex and decimal values

[Michael Kirkham <mikek@muonics.com>]

The definitions for the various integer datatypes say...

  "Values of type [...] may be denoted as decimal or hexadecimal
   numbers. Decimal numbers other than zero MUST NOT have leading zero
   digits. Hexadecimal numbers are prefixed by `0x' and MUST have an
   even number of hexadecimal digits, where letters MAY be upper-case
   but lower-case characters are RECOMMENDED."

It's not clear whether or not the hex values are (or, at least, should be)
allowed to contain leading double-zeros for non-zero values.  This could
perhaps use clarification, or at least a recommended practice.

0x00    -- certainly legal
0x0a    -- certainly legal
0x0abc  -- certainly legal
0x000a  -- is this legal or not?  should it be or should it not be?
           is there a recommended practice?

Note: it is currently allowed by the hexadecimalNumber grammar rule.