Add json plugin for machine parseable output

plugins/help

@@ -20,6 +20,7 @@ sub command :Tab(help,wtf,omgwtfbbq) ($self, $cart, $command, @) {
     # On the other hand, busybox(1) has a "more" applet that gives the user
     # clear instructions and seems mostly harmless too.
     my $pipe;
+    my $oldhandle = select;
     if (open $pipe, "|-", "busybox", "more") {
         select $pipe;
     }
@@ -49,7 +50,7 @@ ${bold}Advanced usage:${off} pass space separated arguments to parameters
 Complete each transaction with ${underline}account${off} (i.e. enter your name).
 END
 
-    select STDOUT;
+    select $oldhandle;
     close $pipe;
 
     return ACCEPT;