Added stringify_as_response func used by __tostring.
Added stringify_as_response func used by __tostring.

zcsteele/turbo,kernelsauce/turbo,zcsteele/turbo,luastoned/turbo,luastoned/turbo,YuanPeir-Chen/turbo-support-mipsel,ddysher/turbo,ddysher/turbo,mniestroj/turbo,YuanPeir-Chen/turbo-support-mipsel