Update for GeoAPI change: Obligation code list replaced by Obligation enum,
for compliance with ISO 19115.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK8@1640667 13f79535-47bb-0310-9956-ffa450edef68
Merge from the JDK8 branch: replaced Obligation CodeList by Enum for ISO 19115 compliance.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK7@1640669 13f79535-47bb-0310-9956-ffa450edef68