Add support for indexed colors

ANSI escape sequences like `\x1b[48;5;10m` were not supported until now.
Specifically, the second attribute, 5, says that the following attribute
is a color index.

The ref tests were updated since `enum Color` variants changed.

1 files changed, 2 insertions, 1 deletions

diff --git a/tests/ref.rs b/tests/ref.rs
index a92da05f..2859dba1 100644
--- a/tests/ref.rs
+++ b/tests/ref.rs
@@ -79,6 +79,7 @@ mod reference {
         vim_simple_edit,
         tmux_htop,
         tmux_git_log,
-        vim_large_window_scroll
+        vim_large_window_scroll,
+        indexed_256_colors
     }
 }