HTTP: remove auto-decoding of UTF-8 content

When READing via HTTP (without /string or /lines), no longer auto-decode
UTF-8 encoded content to a string!. Always return a binary! instead.

The auto-decoding feature removed by this commit lead to brittle code,
when developers testing with a site that by chance returned a string!
were lead to believe that an http:// READ always returns a string!.

This fixes CureCode issue #2027.

Fix as originally suggested by Graham Chiu.
Merge pull request #129 from earl/fix-2027-read-utf8-http

HTTP: remove auto-decoding of UTF-8 content (cc#2027)