Search bar improvements

Reverting to head for layout.jelly, and adding the default `has-default-text` back into the search box

Taking out the `defaulted` js logic with the search-box, and embracing CSS3's 'placeholder' attribute.
Prettying up the search box

offer better pronouns for common job types

[FIXED JENKINS-17125] FingerprintAction no longer need persist the build field thanks to new RunAction2.

[FIXED JENKINS-15587] Do not issue a warning about unparsable build timestamps if it is just a number, i.e. failed symlink.

Not really solving anything here—there is no plausible implementation that could run under these circumstances—
but at least reporting the problem more clearly.

[JENKINS-16276] and various fixes for related exceptions

Otherwise it might try to access a Descriptor that's not yet registered.

Happens when build has no parent:

15:06:14 FATAL: null
15:06:14 java.lang.NullPointerException
15:06:14    at hudson.matrix.MatrixBuild$MatrixBuildExecution.doRun(MatrixBuild.java:371)
15:06:14    at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:580)
15:06:14    at hudson.model.Run.execute(Run.java:1575)
15:06:14    at hudson.matrix.MatrixBuild.run(MatrixBuild.java:304)
15:06:14    at hudson.model.ResourceController.execute(ResourceController.java:88)
15:06:14    at hudson.model.Executor.run(Executor.java:237)
15:06:14    at hudson.model.OneOffExecutor.run(OneOffExecutor.java:66)

Suppressing some known-good instances of an idiom otherwise warned about by NetBeans plugin for Jenkins.