Add some likely aliases for 'show'

If someone starts thinking of it as a filesystem, be obliging.
That means some people might want to 'dir', some people might
want to 'cat' things.  Make it tend to do the right thing.

bin/confetty

@@ -105,7 +105,7 @@ def do_command(command, server):
             if 'error' in res:
                 print target + ': ' + res['error']
                 target = otarget
-    if argv[0] in ('show', 'ls'):
+    if argv[0] in ('cat', 'show', 'ls', 'dir'):
         if len(argv) > 1:
             targpath = fullpath_target(argv[1])
         else: