Add pan and associated files.  This is a lightweight test harness.  It works a
lot like runtests.py did, but it is more powerful.  See the man page for
details.
diff --git a/Makefile b/Makefile
index 926df0b..73ca7fd 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,7 @@
 all: libltp.a
 	@$(MAKE) -C doio $@
 	@$(MAKE) -C tests $@
+	@$(MAKE) -C pan $@
 
 libltp.a:
 	@$(MAKE) -C lib $@
@@ -13,3 +14,4 @@
 	@$(MAKE) -C lib $@
 	@$(MAKE) -C doio $@
 	@$(MAKE) -C tests $@
+	@$(MAKE) -C pan $@