ver 3.3.8
* Support rectangle selection by pressing alt key while selecting.
* Support DECDMAC/DECINVM.
* Start scp by drag&drop a file with shift key to the screen on ssh connection.
* Add --seqfmt/vt_seq_format option.
* Read /dev/kbd on NetBSD/x68k framebuffer.
* Add "Auto detect" entry to "Encoding" tab of mlconfig.
* Add "Local echo" checkbox to "Others" tab in mlconfig.
* Bug fixes:
  Fix weird background picture on NetBSD/x68k Text VRAM by unexpectedly cached pixels.