Join chain definition in xsd should change to edges and paths

Right now, it is

<xs:complexType name="x_joinchain">
<xs:sequence>
<xs:element type="x_tablereferences" name="paths" maxOccurs="unbounded" minOccurs="1"/>
</xs:sequence>
<xs:attribute type="xs:string" name="name" use="required"/>
<xs:attribute type="xs:string" name="description"/>
<xs:attribute type="xs:string" name="display_string"/>
</xs:complexType>

Should be changed to have Paths and Edges.