Fix UnsupportedMediaType in samples

[mdrichardson]

Fixes: https://github.com/microsoft/botbuilder-python/issues/312

Issue Summary

request.headers["Content-Type"] sometimes comes in as

application/json; charset=utf-8

...which causes the 415: UnsupportedMediaType to throw.

Changes

In app.py for the samples, it implements this diff:

@app.route("/api/messages", methods=["POST"])
def messages():
    """Main bot message handler."""
-   if request.headers["Content-Type"] == "application/json":
+   if "application/json" in request.headers["Content-Type"]:
        body = request.json
    else:
        return Response(status=415)

[mdrichardson]

...working on pylint fixes, although the errors don't appear to be related to this PR

[axelsrz]

No, those issues are not related with this PR. I will fix it today and merge this.

[mdrichardson]

@axelsrz No further input needed from me, then?

[axelsrz]

@mdrichardson no