Fix option for tmux 2.0+

CHANGELOG.md

@@ -3,6 +3,7 @@
 ### master
 - update to support \*THE\* latest tmux version
 - bugfix for `prefix + R` key binding
+- fix for tmux 2.0 `default-terminal` option (thanks @kwbr)
 
 ### v2.2.0, 2015-02-10
 - bugfix in `key_binding_not_set`: the regex is now properly detecting key

sensible.tmux

@@ -101,10 +101,14 @@ main() {
 		tmux set-option -g default-command "reattach-to-user-namespace -l $SHELL"
 	fi
 
-	# upgrade $TERM
+	# upgrade $TERM, tmux 1.9
 	if option_value_not_changed "default-terminal" "screen"; then
 		tmux set-option -g default-terminal "screen-256color"
 	fi
+	# upgrade $TERM, tmux 2.0+
+	if server_option_value_not_changed "default-terminal" "screen"; then
+		tmux set-option -s default-terminal "screen-256color"
+	fi
 
 	# emacs key bindings in tmux command prompt (prefix + :) are better than
 	# vi keys, even for vim users