Choose to use 256-colors when $TERM includes 256 (related: #18)

It turned out that Curses.can_change_color? returns false when $TERM is
set to screen-256color, which is perfectly capable of rendering 256
colors.

fzf

@@ -514,7 +514,7 @@ class FZF
     C.noecho
 
     if @color
-      if C.can_change_color? && ENV['TERM'].to_s =~ /256/
+      if ENV['TERM'].to_s =~ /256/
         C.init_pair 1, 110, dbg
         C.init_pair 2, 108, dbg
         C.init_pair 3, 254, 236