implemented Unicode 4-digit and 8-digit parsing, resolves #148 and resolves #167

some examples:
- \u23f0 will be converted to the alarm clock symbol ⏰
- \U1f47d will be converted to the alien emoji 👽

README.md

@@ -103,6 +103,7 @@ Features
  - SSH/Mosh aware split pane (reconnects to remote server)
  - copy to OS clipboard (needs [`reattach-to-user-namespace`][reattach-to-user-namespace]
    on macOS, `xsel` or `xclip` on Linux)
+ - support for 4-digit hexadecimal Unicode characters (requires `perl` or Bash >= 4.1.2)
  - [Facebook PathPicker][] integration if available
  - [Urlview][] integration if available
 
@@ -221,10 +222,10 @@ Then edit the `~/.tmux.conf.local` file (`<prefix> e`) and adjust the following
 variables:
 
 ```
-tmux_conf_theme_left_separator_main=''
-tmux_conf_theme_left_separator_sub=''
-tmux_conf_theme_right_separator_main=''
-tmux_conf_theme_right_separator_sub=''
+tmux_conf_theme_left_separator_main='\uE0B0'
+tmux_conf_theme_left_separator_sub='\uE0B1'
+tmux_conf_theme_right_separator_main='\uE0B2'
+tmux_conf_theme_right_separator_sub='\uE0B3'
 ```
 ### Configuring the status line