Given we feed UTF-8 data into the importer, it must be able to cope
with Unicode. Build md4c with UTF-8 support, advertise it at
usage site, and change a couple of broken decodings.
Driveby: the textedit example used the wrong codec to decode
a Markdown file. While the Markdown spec doesn't deal with encodings,
using the default one for HTML is certainly wrong. Port the loading
of both markdown and plaintext to UTF-8, as that what _saving_
via QTextDocumentWriter would use by default.
Change-Id: I51c6214cfe45ebfc5a67a7366f7866a5328366ec
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>