Add description for base16-solarized theme

Author: mshkrebtan

README.md

@@ -25,11 +25,12 @@ Add plugin to the list of TPM plugins in `.tmux.conf`:
 
 Hit `prefix + I` to fetch the plugin and source it. The plugin should now be working.
 
-3 themes are provided so you can pick and choose via `.tmux.conf` option:
+4 themes are provided so you can pick and choose via `.tmux.conf` option:
 
 - `set -g @colors-solarized '256'` (the default)
 - `set -g @colors-solarized 'dark'`
 - `set -g @colors-solarized 'light'`
+- `set -g @colors-solarized 'base16'`
 
 ## Screenshot
 Here is a screenshot of a tmux session captured from a gnome-terminal using the [dz-version of the awesome Inconsolata font](http://nodnod.net/2009/feb/12/adding-straight-single-and-double-quotes-inconsola/).

tmuxcolors-base16.conf

@@ -1,5 +1,18 @@
 #### COLOUR (base16-solarized)
 
+# This theme is a 256 color variant and it uses the color codes of the
+# base16-solarized (256 color) terminal/shell theme:
+# https://github.com/chriskempson/base16
+# https://github.com/chriskempson/base16-shell
+
+# It is based on the original tmux-colors-solarized light theme with some color
+# codes changed (to map solarized base2, base00, orange, base1).
+
+# In fact, this theme may be used in combination with any base16 256 color
+# terminal/shell theme. But it will probably look a bit 'burnt' (i.e.
+# solarized).  It better matches the base16-solarized-light and
+# base16-solarized-dark terminal/shell color themes.
+
 # default statusbar colors
 set-option -g status-bg colour18 #base2
 set-option -g status-fg yellow #yellow