[PWG5101.1] Issue #106: Section 5.1.5: Restore statements about redundant sizes from MSN1

[Issue Unconfirmed]

The current first paragraph of section 5.1.5 says this:

"For interchange between programs, the dimensions presented in this
specification MUST NOT be converted to another system of units but MUST
remain as defined in this specification."

This is lacking a statement from MSN1 about duplicate sizes. The first
paragraph should say something like this:

"For interchange between programs, the dimensions presented in this
specification MUST NOT be converted to another system of units but MUST
remain as defined in this specification. Furthermore, an identical size
with different units MUST NOT be registered in the IANA Registry. Programs
may convert the dimensions to other units when displaying these names to
human users and for internal use, both of which are outside the scope of
this specification."

Link: http://www.pwg.org/issues/106