Add an option to htdecodetoken to print the file with a token that the tool is reporting on #131
Description
In debugging, it would often be helpful to find exactly what file htdecodetoken is reading from, e.g., in a non-login environment (such as HTCondor) where the user might not be able to easily predict where other software has saved a token and referenced it with an environment variable). Simply adding a flag that would print out the full path to the file that htdecodetoken is reading from would be very helpful.