Updated to maven-plugin 2.0 general release.

(cherry picked from commit 9b53643c7a573f64fe199ca8c9f5b60d8a3d771f)
[FIXED JENKINS-18836][FIXED JENKINS-18879][FIXED JENKINS-19619] Upgrade trilead-ssh to version with the fix

(cherry picked from commit bb265c5e95b0fe39128720b903914236962db41b)

Conflicts:
	changelog.html
[FIXED JENKINS-20085] Overflow in Jenkins.globalIota. Simpler and safer to use an AtomicLong.

(cherry picked from commit 587c6fe317bfe3560069ceb41495c6f5f5d114d1)

Conflicts:
	changelog.html
[FIXED JENKINS-20071] Upgrade bundled versions of credentials and ssh-slaves so we can assume <c:select/> available

(cherry picked from commit 58af1d629a8b1eb9c088b15621b35a22cd770663)

Conflicts:
	changelog.html
[FIXED JENKINS-19947] Restore historical undocumented behavior of a top-level entry in a ZIP.
Noting that various DirScanner implementations handle this inconsistently.

(cherry picked from commit 793b6826e567e20a256a6d4166031e75a185ef7a)

Conflicts:
	changelog.html
[FIXED JENKINS-18633] Simplified distinction between Jenkins.description and View.description.
Both are shown if defined. The edit description link only applies to View.description.
Properly handle a ViewGroup other than Jenkins itself, such as a folder.
(cherry picked from commit 04c8a1efc0f6324868638be9a4cfdb085e17744f)

Conflicts:
	changelog.html