This change adds support for the PMD static analyzer (which is mostly

java-focused). There are two configurable fields: the path to the executable

(which is needed because PMD doesn't really have a good, standard

installation), and the list of rulesets to run.

Posted a big java change and saw that PMD ran and reported the results

  successfully.
Misconfigured the PMD path and saw that the resulting error was reported

  correctly.