SD Declarations and PortTypes
    
      - OGSI models portType inheritance using gwsdl:portType
	
	  - Modeled like W3C proposal for interface inheritance
- GGF commits to moving to WSDL 1.2 when W3C is finished
 
- SDs are inherited down a gwsdl:portType inheritance
	hierarchy
- Overloading is handled like operations
	
	  - SDEs are namespace qualified
- Duplicate SDEs are elided
 
- Values can be associated with (certain) SD Declarations
	
	  - Only SDEs where mutability="static"
- These are like "class constants"
- Values are aggregated down a portType inheritance
	    hierarchy