Allow conditional imports, see examples/playbook3.yml comments for a full explanation. Extensive

refactoring of playbooks now warranted, which we'll do before we move on.   This variable assignment
system makes nearly all possible magic possible, for we can use these variables however we like,
even as module names!

test/TestPlayBook.py

@@ -26,6 +26,15 @@ class TestCallbacks(object):
     def on_start(self):
         self.events.append('start')
 
+    def on_setup_primary(self):
+        self.events.append([ 'primary_setup' ])
+ 
+    def on_setup_secondary(self):
+        self.events.append([ 'secondary_setup' ])
+
+    def on_import_for_host(self, host, filename):
+        self.events.append([ 'import', [ host, filename ]])
+
     def on_task_start(self, name, is_conditional):
         self.events.append([ 'task start', [ name, is_conditional ]])