Change Jenkins to use a single consistent data-binding field.

See also: https://github.com/stapler/stapler/pull/39

This commit includes several changes to accommodate the aforementioned change to Stapler (moving away from 'stapler-class'), as well as to make Jenkins consistently use this same JSON field (moving away from 'kind').


NOTE: Stapler will continue to accept 'stapler-class' for backwards compatibility, and similarly this will continue to pass 'stapler-class' for plugins that have keyed off of it.
Thanks, that is a great little resource.  I hadn't seen that before.

I triaged all of the hits for "kind" (with quotes) in all.git.  I have sorted here by severity.

tl;dr is that there are three plugins that I believe will break if we don't continue to submit/receive "kind".

Repo With Hit | Notes
------------- | -----
elasticbox-plugin | 1 related, needs fix: https://github.com/jenkinsci/elasticbox-plugin/blob/master/src/main/java/com/elasticbox/jenkins/ElasticBoxCloud.java#L500
gcrawler-plugin | 1 related, needs fix: https://github.com/jenkinsci/gcrawler-plugin/blob/master/src/main/java/org/jggug/hudson/plugins/gcrawler/GCrawler.java#L187
multi-slave-config-plugin | 1 related, needs fix: https://github.com/jenkinsci/multi-slave-config-plugin/blob/master/src/main/java/com/sonyericsson/hudson/plugins/multislaveconfigplugin/NodeList.java#L525
jenkins-plugin-runtime.rb | deleting kind (may also need $class deletion)
jenkins.rb | deleting kind (may also need $class deletion)
branch-api-plugin | 1 related, but also submitting stapler-class
coordinator-plugin | 1 related, but also submitting stapler-class
envinject-plugin | 1 related, but also submitting stapler-class
xunit-plugin | 4 unrelated, 1 related but also submitting stapler-class
scriptler-plugin | 3 json tests, which also have stapler-class
sounds-plugin | 1 in a comment: https://github.com/jenkinsci/sounds-plugin/blob/master/src/main/java/net/hurstfrost/hudson/sounds/SoundsBuildTask.java#L59
iOS-AdHoc-Deployment-Plugin | 1 submodule fron jenkins.rb
BlameSubversion-plugin | 4 unrelated
SCTMExecutor-plugin | 10 unrelated
accurev-plugin | 1 unrelated
jenkins | Fixed by PR
metadata-plugin | 2 unrelated
netx | 3 unrelated
pmd-plugin | 1 unrelated
subversion-plugin | 6 unrelated
svn-release-mgr-plugin | 4 unrelated
svnkit | 10 unrelated
ucm4svn-plugin | 1 unrelated
xldeploy-plugin | 1 unrelated