[JENKINS-16341] Amelioration of memory leak by at least interning some heavily redundant strings.
(cherry picked from commit 08efdf5d3ab962cfd4c4c489266592fe1db7df8e)

Conflicts:
	changelog.html
	core/src/main/java/hudson/widgets/RenderOnDemandClosure.java
[JENKINS-16341] INSANE testing shows that a RenderOnDemandClosure binding adds about 380k, with or wothout 08efdf5.(cherry picked from commit f178f0cef4bf86c5fb4cf4a2c40afce4c2b43410)

Conflicts:
	test/src/main/java/org/jvnet/hudson/test/MemoryAssert.java
	test/src/test/java/lib/layout/RenderOnDemandTest.java
[JENKINS-16215] Avoiding unnecessary downloads in FilePath.installIfNecessaryFrom.

The updated version uses the locally cached timestamp, '.timestamp', to set the
'If-Modified-Since' header. 304 Not Modified responses are dealt with by
aborting the installation.
(cherry picked from commit 35f7653b7b28bb65b116f16282d9bea567405f61)

Conflicts:
	core/src/test/java/hudson/FilePathTest.java
[JENKINS-16215] : changelog(cherry picked from commit 19b31687c870bba50bb181c5d08486151b1839a9)

Conflicts:
	changelog.html
[JENKINS-15466] remember the cause of the initialization failure given that JVM doesn't remember.
(cherry picked from commit 7e8bf72eac30952c33d8dabb653bf87cd25ff991)
Properly inherit adjuncts into renderOnDemand lazy pieces
(cherry picked from commit 6f7891f3b853b72f8f17ed409e9e09929de37d7c)

Conflicts:
	core/src/main/java/hudson/widgets/RenderOnDemandClosure.java
Resolve forgotten cherry-pick conflict
Verifying that the heap size of a SuiteResult (from Surefire) is linear in the sizes of TEST-*.xml + *-output.txt even when there is lots of stdio.(cherry picked from commit 9f22e33ebd4a1e2933472d52d7ce1b903c0c5f6a)

Conflicts:
	test/src/main/java/org/jvnet/hudson/test/MemoryAssert.java