fixes WiC64 by using curl_multi_poll()
-debugcart breaks snapshot writing
WiC64: disable coloring in log-files, add background col; log.c: avoid closing stdout
cmd_http_get_encoded: fixed signed/unsigned bug in URL encoder
hexdump: avoid chars < 32 even if printable (e.g. tabs) in ascii dump
WiC64: fixed some docs
WiC64: on wic64 reset, also reset remote timeout to factory default (5s).
Added option `-wic64remotetimeout', resources and GUI elements accordingly.