Avoid putting colors in private chat names
Avoid putting colors in private chat names

Channel names in weechat are simple strings that should not have
colors embedded, so don't do that (unless overridden by a
configuration setting).

In addition, remove channels_not_on_current_server_color support.

Fixes #73

wee-slack/wee-slack,trygveaa/wee-slack,rawdigits/wee-slack,scharfie/wee-slack,megalithic/wee-slack