Mark html page as being utf-8
Mark html page as being utf-8

FireFox complained when opening the page without proper indication of the
encoding.

Change-Id: I4f0891699c72d46bcf0cd488e2ecaf095514fabc
Reviewed-by: Kurt Pattyn <da83d6ada5df79ff647b4271d0d788c6f1bafca2@gmail.com>

SfietKonstantin/qtwebsockets,pixty/qtwebsockets,remimixlr/QtWebsocket,pixty/qtwebsockets