JSON serializer handles utf8 charset.

Make serializer and deserializer use utf8 => 1 if the option isn't
otherwise defined.

Closes #228
Convert the README to markdown and add more content.
Removing perl-5.18 as a target for Travis.

The build keeps failing with this version.  When we find the cause we
can put back this version.
Remove old version of TODO file; keep new version
The TODO-Documentation file is not needed anymore.

Tickets have been created for the missing documentations.