Load JSON internally by default

why not?

main/distro/all/all.go

@@ -59,9 +59,9 @@ import (
 
 	// JSON config support. Choose only one from the two below.
 	// The following line loads JSON from v2ctl
-	_ "v2ray.com/core/main/json"
+	// _ "v2ray.com/core/main/json"
 	// The following line loads JSON internally
-	// _ "v2ray.com/core/main/jsonem"
+	_ "v2ray.com/core/main/jsonem"
 
 	// Load config from file or http(s)
 	_ "v2ray.com/core/main/confloader/external"