Add hook post-clone-cleared

doc/hooks

 Available hooks are:
-pre-command
-post-command
-pre-enter
-post-enter
-pre-run
-post-run
-pre-upgrade
-post-upgrade
+
+* pre-command
+* post-command
+* pre-hook
+* post-hook
+* post-hook-cleared
+	use this if you need to operate on different git repositories after cloning
+* pre-enter
+* post-enter
+* pre-run
+* post-run
+* pre-upgrade
+* post-upgrade

vcsh

@@ -153,6 +153,8 @@ clone() {
   Once this situation has been resolved, run 'vcsh run $VCSH_REPO_NAME git pull' to finish cloning.\n" 17
 	git merge origin/master
 	hook post-clone
+	retire
+	hook post-clone-retired
 }
 
 delete() {