When moving the configuration files to $XDG_CONFIG_HOME I forgot to
change the line in .bashrc that sources the tmux configuration so bash
was still trying to source ~/.tmux.conf, which no longer exists.
This commit fixes that. Additionally, the color setting code has been
factored out of tmux.conf into tmux-colors.conf (which can be sourced
from bash profile and tmux.conf). This way the rest of the code in
tmux.conf doesn't have to be executed again when changing the background
color.
Fernando Schauenburg
6b4f2ecf85