tests/test-bad-pull.t

i18n: calculate terminal columns by width information of each characters

neither number of 'bytes' in any encoding nor 'characters' is
appropriate to calculate terminal columns for specified string.

this patch modifies MBTextWrapper for:

  - overriding '_wrap_chunks()' to make it use not built-in 'len()'
    but 'encoding.colwidth()' for columns of string

  - fixing '_cutdown()' to make it use 'encoding.colwidth()' instead
    of local, similar but incorrect implementation

this patch also modifies 'encoding.py':

  - dividing 'colwith()' into 2 pieces: one for calculation columns of
    specified UNICODE string, and another for rest part of original
    one. the former is used from MBTextWrapper in 'util.py'.

  - preventing 'colwidth()' from evaluating HGENCODINGAMBIGUOUS
    configuration per each invocation: 'unicodedata.east_asian_width'
    checking is kept intact for reducing startup cost.

  $ hg clone http://localhost:$HGPORT/ copy
  abort: error: Connection refused
  [255]

  $ test -d copy || echo copy: No such file or directory
  copy: No such file or directory

  $ cat > dumb.py <<EOF
  > import BaseHTTPServer, SimpleHTTPServer, os, signal
  > def run(server_class=BaseHTTPServer.HTTPServer,
  >         handler_class=SimpleHTTPServer.SimpleHTTPRequestHandler):
  >     server_address = ('localhost', int(os.environ['HGPORT']))
  >     httpd = server_class(server_address, handler_class)
  >     httpd.serve_forever()
  > signal.signal(signal.SIGTERM, lambda x: sys.exit(0))
  > run()
  > EOF

  $ python dumb.py 2>/dev/null &
  $ echo $! >> $DAEMON_PIDS

give the server some time to start running

  $ sleep 1

  $ hg clone http://localhost:$HGPORT/foo copy2 2>&1
  abort: HTTP Error 404: * (glob)
  [255]

  $ kill $!