[wsrp-wsia] [change request #75] Property usage

[Rich Thompson <richt2@us.ibm.com>]

Section: 5.1.15 PropertyDescription
Page/Line: 25
Requestedby: Andre Kramer
Old text: 
Proposed text: [O] string propertyUsage
propertyUsage: Describes whether the property is read-only (propertyUsage 
== "readOnly") or optional (propertyUsage == "optional"); with the 
Producer supplying a default value for optional properties.

Reasoning: Property types are overloaded for Portlet and Registration 
properties and we have no way to indicate which are optional and which are 
read-only (especially important for registration). Not clear if consumer 
can currently ignore registration properties it does not understand.