Controller-side module caching.

This makes our recursive, ast.parse performance measures as fast as
pre-ziploader baseline.

Since this unittest isn't testing that the returned module data is
correct we don't need to worry about os.rename not having any module
data.  Should devise a separate test for the module and caching code

examples/ansible.cfg

@@ -14,6 +14,7 @@
 #inventory      = /etc/ansible/hosts
 #library        = /usr/share/my_modules/
 #remote_tmp     = $HOME/.ansible/tmp
+#local_tmp      = $HOME/.ansible/tmp
 #forks          = 5
 #poll_interval  = 15
 #sudo_user      = root