Centralize Maven reporting plugin configuration

[DavidWhitlock]

Currently, there are a lot of duplicate reporting plugin declarations (jxr, jdepend, checkstyle, etc.) in various pom.xml files. As a result, when we update the version or configuration of one of these plugins, we have to modify a number of different places.

It looks like the reporting plugin configuration is inherited from the parent project. So, I should move as many of the configurations to the parent project as I can.

I've already done this with the findbugs, javadoc, and pmd plugins while addressing #44. So, I think it works fine.

[DavidWhitlock]

While I'm at it, I should make sure that the results of the integration tests (failsafe plugin) are included in the reports.

[DavidWhitlock]

Hmm. It looks like the surefire and failsafe reports are still not included in the site: http://davidwhitlock.github.io/PortlandStateJava/grader/project-reports.html