A job without a firstBuild is not causing an NPE anymore.

build

logic to get remote settings.xml file, test in this order (as maven do)
1. configured alternateSettings
2. ~/.m2/settings.xml
3. $M2_HOME/conf/settings.xml

This is a proof of concept to core modulizarion (by binary integration.)
A module is built like a plugin but it's packaged to the war as a
WEB-INF/lib/*.jar, not as a plugin.

Compared to plugins, jars integrated in this way do not double-package
dependency jars, and they are not visible to the users. I plan to try a
few of these and if it's useful, this could be an useful mechanism for
modularizing core.

[FIXED JENKINS-9102] Changed buildListTable column name from Date to Time Since, to reflect actual content.

Added a configuration option to control initialization of the
environment of the Jenkins server process.