* updated shebang
* The script now compares its version number to the one online. If there is a newer version of `updater.sh` online it ask the user if he wants to download and run it.
* 2 parameters are supported: `-donotupdate` to disable the update-check and `-update` to auto-download and run the new version without asking
* Backup files are now saved to the directory `userjs_backups` instead of causing more bloat in the profile directory.
this should now work no matter how the script is called (including symlinks) on both Mac and Linux.
+ Storing and restoring the original working directory to prevent problems in certain circumstances.
