Changes on data input type - accepting only json now.

Hello everyone, Tago will support only application/json as default content-type from your device data post. It means that you cannot use application/x-www-form-urlencoded or other standards anymore. This change is important to keep the original type of your values on the body scope. We are doing this change to avoid any data format error.

This new change is already effective since 30th Nov.