1. proxycygterm.cc:
  1. make it 8-bit transparent in direction from shell to terminal
  2. re-check telnet NAWS exchange to make sure terminal to shell direction is also 8-bit transparent
  1. UTF-8 to UTF-16 decoder in terminal, terminal buffer is now UTF-16
  2. still need to work on more precise drawing of Unicode text (font mapping, multiple UTF-16 chars per screen char cell, two display widths for CJK chars).