Rethink colors

Use LS_COLORS to print default color of each file or folder

Keep showing largest sub folder in red.

tests/tests.rs

@@ -7,13 +7,21 @@ pub fn test_basic_output() {
     assert_cli::Assert::main_binary()
         .with_args(&["src/test_dir/"])
         .stdout()
-        .contains(" ┌─┴ test_dir ")
+        .contains(" ┌─┴ ")
         .stdout()
-        .contains("  ┌─┴ many ")
+        .contains("test_dir ")
         .stdout()
-        .contains("    ├── hello_file")
+        .contains("  ┌─┴ ")
         .stdout()
-        .contains("     ┌── a_file ")
+        .contains("many ")
+        .stdout()
+        .contains("    ├── ")
+        .stdout()
+        .contains("hello_file")
+        .stdout()
+        .contains("     ┌── ")
+        .stdout()
+        .contains("a_file ")
         .unwrap();
 }