Add option to turn on JSON pretty printing in monitor

Expaned '-mon' arg to allow a 'pretty=on' flag. This makes the
monitor pretty print its replies to easy human debugging / reading

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
diff --git a/qemu-config.c b/qemu-config.c
index e3b746c..6052a28 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -283,6 +283,9 @@
         },{
             .name = "default",
             .type = QEMU_OPT_BOOL,
+        },{
+            .name = "pretty",
+            .type = QEMU_OPT_BOOL,
         },
         { /* end of list */ }
     },