Continued implementation of extended attributes.

* Changed the `Issue` constructor to use an attribute map instead of an
  increasingly long parameter list. Of course we lose some control over required
  parameters.
* Added the Joda Time and SLF4J logging libraries.
* Implemented the `FileIssue` constructor for the new `Issue` refactor.

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

@@ -2,7 +2,7 @@ package com.jdbernard.pit
 
 public class MockIssue extends Issue {
     public MockIssue(String id, Category c, Status s, int p) {
-        super (id, c, s, p)
+        super ([id: id, category: c, status: s, priority: p])
     }
     public boolean delete() { return true }
 }

libpit/test/com/jdbernard/pit/file/FileIssueTest.groovy

@@ -171,9 +171,7 @@ class FileIssueTest {
         assertEquals issue.status    , Status.NEW
         assertEquals issue.priority  , 1
         assertEquals issue.title     , "Add the killer feature to the killer app."
-        assertEquals issue.text      , "Add the killer feature to the killer app.\n" +
-                                      "=========================================\n\n" +
-                                      "Make our killer app shine!."
+        assertEquals issue.text      , "Make our killer app shine!."
         assertEquals issue.source    , issueFile
     }