Add getFieldOrder() methods.

Add getFieldOrder() methods to classes which extend com.sun.jna.Structure,
for compatibility with newer versions of JNA.  [JENKINS-24521]
[maven-release-plugin] prepare release jenkins-1.582
[maven-release-plugin] prepare for next development iteration
updated changelog for release
Merge pull request #1410 from rodrigc/JENKINS-24521

Add getFieldOrder() methods.
updated changelog as a part of the release
merged back the RC branch