[FIXED JENKINS-22514] In ZIP archives file separator must be '/'
[JENKINS-2786] Makes no sense for Computer.currentComputer to return MasterComputer when not on an executor thread.
Junit 4
Introduce FormValidation#aggregate
Merge pull request #1458 from olivergondza/aggregate-validations

Aggregate multiple FormValidations into one
Noting #1458 and #1456
[maven-release-plugin] prepare release jenkins-1.589
[maven-release-plugin] prepare for next development iteration
updated changelog for release
updated changelog as a part of the release
merged back the RC branch
Merge pull request #1408 from howlger/master

[FIXED JENKINS-22514] In ZIP archives file separator must be '/'
Noting https://github.com/jenkinsci/jenkins/pull/1408

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>
Noting https://github.com/jenkinsci/jenkins/pull/1268 , cleanup of previous changelogs

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>
creating an RC branch
the trunk is toward 1.591-SNAPSHOT
Merge remote-tracking branch 'origin/master'
Fix 1.589 changes
Merge branch 'Computer.currentComputer-JENKINS-2786'
Expanding Javadoc from #1454 as suggested by @oleg-nenashev.