Simplify logging a bit
Fix configuration value for untag
Considerably simplify watch loop

I wonder at times what was I thinking when I originally wrote it...
Add support for setuid scripts

If we detect a script with setuid flag set (+s) we setuid to owner of that
script file before actually calling exec. This way we can have some scripts
running with lower permissions than root even if some require root.

Fixes #3
Simplify __run_scripts loop over script_dir

We now also warn about non-executable files in script_dir