Unreliable connection between standalone Blockly and asebahttp

Created by: ypiguet-epfl

Sending an application from Thymio Blockly (standalone application) to asebahttp (whether launched by Thymio Web Bridge or directly) is very unreliable (tested in 1.6 on macOS 10.12 and Chrome 63, also with other web applications using an entirely different code base; Firefox is slightly better). Reloading the web page helps (except that the Blockly program is lost).

After initial investigation, a potential culprit could be that Chrome doesn't like the 204 status code sent by method PUT in http.cpp (method HttpInterface::evLoad). The XmlHttpRequest doesn't terminate successfully and discussions about this issue can be found on the web. A dummy reply with status 200 could be a solution.