Sub-objects are never indexed when explicit es_indexed: true is used. This fixes that. Fixes jamescarr/mongoosastic#69.

Sub-objects are never indexed when explicit es_indexed: true is used. This fixes that. Fixes jamescarr/mongoosastic#69.

The solution isn't fantastic. Unfortunately sub-objects are *always* indexed now once `es_indexed: true` is used. However if you have at least one `es_indexed: true` in the sub-object then the other properties won't come through. Probably good enough for now.