As the title suggests, now the program renames the first file and subsequent files starting with the number '1' instead of '0' previously. This way you would be able to check exactly which file is which according to number, logically, a little more easily (before you may have had to add 1 to the number in your head).
Also added a terms.txt file to assume responsibility of using this program. In its current state, misuse of the extension could lead to loss of files if you don't specify correctly. So be careful, and let me know if you find this useful, so I can get motivated to release updates such as dealing with multiple extensions and failsafes.