Add comments in the top-level readme file for the tools folder

Author: Thomas Krinke

README.md

@@ -29,3 +29,7 @@ Pre-requisites:
 - NetBackup 8.1.1 or higher
 - See script README for perl requirements and usage
 
+#### tools
+The tools folder contains utilities that have proven useful in the development of projects using
+NetBackup REST APIs, but do not provide any API usage examples.  Again, these tools are not for
+production use, but they may be of some use in your work.