No reason to push the content-type decision into httpclient

Previous commits went back and forth a bit on whether the various APIs
should use bytes or strings, but bytes appears to be a better answer,
because actual data in streams will always be 7-bit ASCII or raw
binary.  There's no reason to apply the performance penalty of
constantly converting between bytes and strings.

One drawback now is that lots of code now has to have "b" prefixes on
strings, especially in tests, which inflates this commit quite a bit.

This can hit a deadlock waiting for the thread to exit.  We don't
need to wait; it will die when it can, or get terminated when the
interpreter exits.

Uses utf-8, or whatever the server response indicates.

Main change is to use raw bytes for filenames everywhere

The default bisect module includes a fast C implementation, which
requires that array indices fit within the system "long" type.  For
32-bit systems, that's not acceptable, as the table indices for raw
data can exceed 2^32 very quickly.  A pure python version works fine.

The new version works in Cherrypy 3.2