fix usage string indentation

lib/api/screenboard.js

@@ -184,11 +184,11 @@ module.exports = {
     share: share,
     getUsage: function(){
         return [
-            "dogapi screenboard create <title> <description> <graphs> [--tmpvars <templateVariables>] [--width <width>] [--height <height>]",
-            "dogapi screenboard remove <boardId>",
-            "dogapi screenboard get <boardId>",
-            "dogapi screenboard getall",
-            "dogapi screenboard share <boardId>"
+            "  dogapi screenboard create <title> <description> <graphs> [--tmpvars <templateVariables>] [--width <width>] [--height <height>]",
+            "  dogapi screenboard remove <boardId>",
+            "  dogapi screenboard get <boardId>",
+            "  dogapi screenboard getall",
+            "  dogapi screenboard share <boardId>"
         ];
     },
     getHelp: function(){