wireprotov1server: use binascii.unhexlify
The "hex" codec doesn't exist in Python 3. We could use
`codecs.decode(h, 'hex_codec')`. But `binascii.unhexlify()`
exists and should work the same on Python 2 and 3.
Differential Revision: https://phab.mercurial-scm.org/D5755
Mercurial's documentation is kept in reStructuredText format, which is
a simple plain text format that's easy to read and edit:
http://docutils.sourceforge.net/rst.html
It's also convertible to a variety of other formats including standard
UNIX man page format and HTML. You'll need to install Docutils:
http://docutils.sourceforge.net/
Use the Makefile in this directory to generate the man and HTML pages.