[JENKINS-13202] 646154f1 refinement: resolveSymlink is documented to return null, not throw an exception, when called on a regular file.

The bug was actually already fixed and moreover this could cause that fireCompleted won't be called in case that cleanUp throws an exception, see commentes under https://github.com/jenkinsci/jenkins/commit/51f715162eba4dd1c4e081ec15c7ceb12e813ca5

Prevent to exception which causes that build will not be saved.

Conflicts:
	changelog.html

[JENKINS-15367] Fix Maven downstream resolution when declared as a specific version.

Document when EnvVars.get() function was added.

Set source/target level to 1.6 within the m2e profile.

Otherwise, eclipse gets unhappy with the @Override annotations.

inverse maven-plugin -> config-file-provider dependency

Added link to the pull request for "Changed defaults for the Mac installer to make iOS codesigning easier" in ChangeLog

Added link to the pull request of "Changed defaults for the Mac installer to make iOS codesigning easier"

[FIXED JENKINS-15733] ArrayIndexOutOfBoundsException from Launcher due to misinterpretation of ProcStarter.envs in f5cebdc8.
(Should this field be made a [LinkedHash]Map<String,String> or even EnvVars?
It is protected in a final class, so effectively package-private, thus not a b/w compat issue.)