Re-add solarized tmux colours file from github

This is so that it will be easier to check for updates and replace. The
file is exactly as is found in the original repo. Eventually, we will
have a make task that recopies these files, like how vim-plug's
`PlugUpgrade` works.

tmux/tmuxcolors-256.conf

@@ -0,0 +1,34 @@
+#### COLOUR (Solarized 256)
+
+# default statusbar colors
+set-option -g status-bg colour235 #base02
+set-option -g status-fg colour136 #yellow
+set-option -g status-attr default
+
+# default window title colors
+set-window-option -g window-status-fg colour244 #base0
+set-window-option -g window-status-bg default
+#set-window-option -g window-status-attr dim
+
+# active window title colors
+set-window-option -g window-status-current-fg colour166 #orange
+set-window-option -g window-status-current-bg default
+#set-window-option -g window-status-current-attr bright
+
+# pane border
+set-option -g pane-border-fg colour235 #base02
+set-option -g pane-active-border-fg colour240 #base01
+
+# message text
+set-option -g message-bg colour235 #base02
+set-option -g message-fg colour166 #orange
+
+# pane number display
+set-option -g display-panes-active-colour colour33 #blue
+set-option -g display-panes-colour colour166 #orange
+
+# clock
+set-window-option -g clock-mode-colour colour64 #green
+
+# bell
+set-window-option -g window-status-bell-style fg=colour235,bg=colour160 #base02, red

tmux/tmuxcolours.conf

@@ -1,4 +1,6 @@
 # vim: ft=tmux
+# https://raw.githubusercontent.com/seebi/tmux-colors-solarized/master/tmuxcolors-256.conf
+source-file ~/dotfiles/tmux/tmuxcolors-256.conf
 
 # Default status line options.
 set-option -g status on
@@ -25,29 +27,4 @@ set-option -g status-right-length 90
 set-option -g status-right '#[fg=colour233]#[fg=colour166,bg=colour233] %H:%M #[fg=colour233,bg=colour166]%d/%m/%y #(rainbarf --remaining --rgb --width 10)'
 
 
-# Other colour defaults from Solarized 256 (https://github.com/seebi/tmux-colors-solarized)
-
-# default window title colors
-set-window-option -g window-status-fg colour244 #base0
-set-window-option -g window-status-bg default
-
-# active window title colors
-set-window-option -g window-status-current-fg colour166 #orange
-set-window-option -g window-status-current-bg default
-
-# pane border
-set-option -g pane-border-fg colour235 #base02
-set-option -g pane-active-border-fg colour240 #base01
-
-# message text
-set-option -g message-bg colour235 #base02
-set-option -g message-fg colour166 #orange
-
-# pane number display
-set-option -g display-panes-active-colour colour33 #blue
-set-option -g display-panes-colour colour166 #orange
-
-# clock
-set-window-option -g clock-mode-colour colour64 #green
-
 if-shell '[[ $(version-compare $(tmux -V | sed "s/[tmux ]//g") 2.1) -ge 0 ]]' 'source-file ~/dotfiles/tmux/tmuxcolours2.conf'