DDSSEC_ — The example governance does not validate with the governance XSD

The Example machine readable file example_governance.xml has two problems:
(1) Inside the <domain_rule> it uses an the element name "allow_unauthenticated_participants" whereas the Governance XSD calls this element "allow_unauthenticated_join"

(2) The governance document specifies the DomainRule as <xs:sequence> of various elements. These forces the elements to appear always in that exact order. The example puts the elements inside the <domain_rule> in a different order

The (1) should be corrected in the example_governance.xml file. The element name "allow_unauthenticated_join" appears in the spec in several places and it seems simpler to retain it rather than change it. Although it does make it somewhat inconsistent with the name used in the ParticipantSecurityAttributes.

Either reorder the elements in the example_governance.xml inside<domain_rule> or else change the dds_security_governance.xsd to use <xs:all> as this construct allows the elements to appear in any order and still preserves the constraint that each element can appear at most once.

Make Governance consistent with example and Attribute naming

Modify governance to make it consistent with naming of ParticipantSecurityAttributes and the example governance document: allow_unauthenticated_join -> allow_unauthenticated_participants

Also address issue http://issues.omg.org/browse/DDSSEC_-135 by using xs:boolean instead of BooleanKind
And the suggested change to the schema for <domains> that appeared in the comments to http://issues.omg.org/browse/DDSSEC_-131 but could not be done there because 131 was already closed.