Simplified the ResponseMetaData class by removing all the UTF-8 forced signaling machinery
Made ResponseMetaData standard-compliant by defaulting to "latin1" for decoding when no charset information is provided by the server.
Using the BOM, rather than HTTP headers, as a more robust and timely means to enforce UTF-8 re-encoding when (and only when) we actually had to modify the response content.
Added sniffing of in-content charset information ( tags and BOM) when it's not delivered by HTTP headers.
All this should fix a whole bunch of decoding and encoding bugs, including https://lists.gnu.org/archive/html/bug-librejs/2019-02/msg00004.html and http://savannah.gnu.org/bugs/?54857
All this should fix a whole bunch of decoding and encoding bugs, including https://lists.gnu.org/archive/html/bug-librejs/2019-02/msg00004.html and http://savannah.gnu.org/bugs/?54857