Fixed the bug in testing when non-source files are open. DrJava now only confirms that files with the extensions ".java", ".dj0", ".dj1", and ".dj2" have been compiled before running junit on TestCase classes. Moved the methods in GlobalModelNaming to the interface OpenDefinitionsDocument and its implementation as the innner class ConcreteOpenDefDoc (within AbstractGlobalModel and DefaultGlobalModel). The class GlobalModelNaming is no longer used and can be removed.