[JENKINS-23561] [JENKINS-23030] Use customized matrix tag

[JENKINS-23561] (https://issues.jenkins-ci.org/browse/JENKINS-23561)
[JENKINS-23030] (https://issues.jenkins-ci.org/browse/JENKINS-23030)

Matrix combinations parameter plugin uses /lib/hudson/project/matrix tag.
That tag is moved to matrix-plugin since Jenkins 1.561, and renamed to /lib/hudson/matrix-project/matrix. That results this plugin does not work on Jenkins >= 1.561.

This change does followings:
* Added regression tests for HTML renderings.
* Have a copy of /lib/hudson/project/matrix in this plugin.
* Applies that tag also to value.groovy.
* Avoids NPE for the case `Layouter` of `MatrixProject.getLayouter` returns null.
    * As far as I tested, this is a case only when a combination filter completely invalidates an axis.

This is an alternate fix for #5, #6.