fix bug of erasing the temp .avi file created by mencoder because
[booh] / lib / booh /
drwxr-xr-x   ..
-rw-r--r-- 11392 GtkAutoTable.rb
-rw-r--r-- 2259 UndoHandler.rb
-rw-r--r-- 17151 booh-lib.rb
-rw-r--r-- 14027 html-merges.rb
-rw-r--r-- 611 pre-setup.rb