[PWG5100.19] Issue #134: Add sub-section to section 4 discussing options for how a Client monitors Printer status

[Issue Unconfirmed]

A Client can use various attributes to monitor a Printer's status. Discuss
options for methodologies for interpreting different attributes
(printer-state, printer-state-reasons, printer-state-message, among others)
and also discuss related logic.

Link: http://www.pwg.org/issues/134