* Keeps a list of the parameters defined for a project.
*
* <p>
* This class also implements {@link Action} so that <tt>index.jelly</tt> provides
* This class also implements {@link Action} so that {@code index.jelly} provides
* a form to enter build parameters.
* <p>The owning job needs a {@code sidepanel.jelly} and should have web methods delegating to {@link ParameterizedJobMixIn#doBuild} and {@link ParameterizedJobMixIn#doBuildWithParameters}.
* When an HTTP request arrives with an HTTP basic auth header, this filter detects
* that and emulate an invocation of <tt>/j_security_check</tt>
* that and emulate an invocation of {@code /j_security_check}
* (see <a href="http://mail-archives.apache.org/mod_mbox/tomcat-users/200105.mbox/%3C9005C0C9C85BD31181B20060085DAC8B10C8EF@tuvi.andmevara.ee%3E">this page</a> for the original technique.)
*
* <p>
* This causes the container to perform authentication, but there's no way
* to find out whether the user has been successfully authenticated or not.
* So to find this out, we then redirect the user to