Included patch for persistent undo.  Lots of changes and added test.
diff --git a/src/buffer.c b/src/buffer.c
index 531e4b9..5ecb638 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -61,8 +61,9 @@
 #endif
 
 /*
- * Open current buffer, that is: open the memfile and read the file into memory
- * return FAIL for failure, OK otherwise
+ * Open current buffer, that is: open the memfile and read the file into
+ * memory.
+ * Return FAIL for failure, OK otherwise.
  */
     int
 open_buffer(read_stdin, eap)