Fixed FileProject.delete() bug. Preparing for libpit 1.1.6

libpit/src/com/jdbernard/pit/FileIssue.groovy

@@ -41,6 +41,8 @@ public class FileIssue extends Issue {
         source.write(text)
     }
 
+    public boolean delete() { return source.delete() }
+
     public static boolean isValidFilename(String name) {
         return name ==~ /(\d+)([bcft])(\d).*/
     }

libpit/src/com/jdbernard/pit/FileProject.groovy

@@ -72,7 +72,7 @@ class FileProject extends Project {
         return new FileProject(newDir)
     }
 
-    public boolean delete() { return source.delete() }
+    public boolean delete() { return source.deleteDir() }
 
     @Override
     public String toString() { return name }

libpit/src/com/jdbernard/pit/Issue.groovy

@@ -2,7 +2,7 @@ package com.jdbernard.pit
 
 import java.lang.IllegalArgumentException as IAE
 
-public class Issue {
+public abstract class Issue {
 
     protected String id
     protected Category category
@@ -38,4 +38,6 @@ public class Issue {
 
     @Override
     public String toString() { return "${id}(${priority}): ${category} ${title}" }
+
+    public abstract boolean delete()
 }