A few changes

I've made a few changes to functionality and beautified the code slighty:

* Added a shebang at the beginning per scripting conventions.
* Beautified the comments a bit to help code readability.
* Added *-rt* options to the 'ls' command. This sorts by time and reverses it, so that the files with the newest time stamps are at the bottom. Useful when tailing.
* Renamed the file from customwatch.sh to customwatch, just to make it more pleasant to type.