Add infinite duration option to - showfake, make reload command warn on script errors, fix 338

- showfake with duration:0 is now considered infinite (Idea mentioned in the IRC)
- /denizen reload scripts (or -a) will now warn the user if there was an error (Idea mentioned in the IRC)
- spawn skeleton will receive a bow, pig_zombie receives a gold sword (Issue 338)

This has, of course, been fully tested. It all works!