Fixed ugly inheritance issue with Issue and FileIssue.

Added Filter unit tests.

libpit/test/com/jdbernard/pit/FileProjectTest.groovy

@@ -136,6 +136,7 @@ class FileProjectTest {
         assertEquals newIssue.text, 'A newly made bug report.\n'+
                                     '========================\n\n' +
                                     'Testing the Project.createNewIssue() method.'
+        assertEquals rootProj.issues[(newIssue.id)], newIssue
 
         //test defaults and creation of issue in an empty project
         newIssue = rootProj.projects.emptyproj.createNewIssue()
@@ -145,6 +146,9 @@ class FileProjectTest {
         assertEquals newIssue.text,     'Default issue title.\n' +
                                         '====================\n'
 
+        assertEquals rootProj.projects.emptyproj.issues[(newIssue.id)],
+            newIssue
+
     }
 
 }

libpit/test/com/jdbernard/pit/FilterTest.groovy

@@ -94,4 +94,12 @@ class FilterTest {
 
     }
 
+    @Test void testAcceptsProjectsFilter() {
+
+    }
+
+    @Test void testCompositeFilter() {
+
+    }
+
 }